Founded in 1920，Communist Party of Australia is an important force in the world socialist movement.So far it has gone through nearly a century of ups and downs.Since its establishment，Communist Party of Australia has adhered to the theoretical guidance of Marxism-Leninism and united the Australian working class and working people to carry out a heroic struggle against the decadent reactionary rule of monopoly capital，in order to maintain political and economic interests of the Australian people and push forward social progress.

In the guidance of Marxism，this paper mainly focuses on expounding and analysizing the socialist theory and practice of the Communist Party of Australia，and the success or failure of the socialist movement in Australia during the 20th century.This paper is divided into several parts，including“Introduction”，“The difficult and tortuous course of development of the Australian Communist Party”，“The Rethink on Capitalism and Socialism by Communist Party of Australia since the Collapse of the former Soviet Union and East Europe”，“The Exploration on the Path of Socialist Development by the Communist Party of Australia”，“Communist Party of Australia Strenghtens Party Building”，“The Practice of Communist Party of Australia”and“The Evaluation of the Socialist Theory and Practice of Communist Party of Australia”.

The Introduction section analysizes the significance of the topic，research status，the study object，the basic ideas and research methods，innovations and inadequacies of this article.

Regarding the major events in the history of the Communist Party of Australia as landmarks，the first part divides the difficult and tortuous 92 years’course of development of the Australian Communist Party into five stages：the establishment of the Communist Party of Australia and its early struggle（1921-1931）；the development of the Communist Party of Australia during the anti-fascist period（1932-1945）；the anti-communist policies of the Menzies government and the struggle of the Communist Party of Australia（1946-1955）；the split of the Communist Party of Australia and the decline of Communist Party of Australia（1956-1990）；the reconstruction and new explorations of the Communist Party of Australia（1990-present）.

The second part describes the critique of contemporary capitalism and the explorations of socialism by Communist Party of Australia since the Collapse of the former Soviet Union and East Europe，including the analysis of globalization of capitalism，the capitalist economic crisis and environmental crisis，the Collapse of the former Soviet Union and East Europe and world socialist movement by Communist Party of Australia.Communist Party of Australia believes that the nature of current economic globalization is the globalization of capitalism，which has caused serious consequences for social development.At the same time，the capitalist economic crisis that has sweeped the world and the deepening environmental crisis is caused by its own contradictions of the capitalist system.They can not be avoided.The only way to fundamentally solve the problems of the capitalist economic crisis and environmental crisis is replacing capitalism with socialism.Through the critique of contemporary capitalism，Communist Party of Australia proved the necessity and inevitability of replacing capitalism with socialism.Meanwhile，Communist Party of Australia spoke highly of the major achievements of the world socialist movement in the 20th century，reviewed the reasons of the Collapse of the former Soviet Union and East Europe and analyzed the world socialist movement.

The third part describes and analyzes the exploration of the path of socialist development by the Communist Party of Australia since the Collapse of the former Soviet Union and East Europe.This section first describes and analysizes Australia’s social nature，class structure and main social contradictions.Based on this，this paper analysizes Communist Party of Australia’s theory about the nature and stage of the social revolution in Australia，Australia’s future socialist society and the peaceful and democratic path of socialist development，as well as its united front strategy.

The fourth part mainly expounds Communist Party of Australia’s practice to strengthen party building.This part analysizes party building initiatives of Communist Party of Australia that includes the ideological，organizational and political party building measures.In terms of ideological construction，Communist Party of Australia focuses on strengthening the learning and application of knowledge of Marxism-Leninism，discussed and analyzed in-depth the capitalist economic crisis，criticizes leftist adventurism and right opportunism.In terms of organization building，Communist Party of Australia prescribes strict procedures for joining the party and the obligations that the party members need to fulfill.It stresses the need to adhere to the organizing principle of democratic centralism，strengthen the party ranks and strengthen the Central Committee and the building of party branches.It provides for strict party discipline.In terms of political construction，Communist Party of Australia clearly set up the party’s political program and political line.It continues to enrich and develop them and publicize them.Meanwhile，Communist Party of Australia stressed the need to strengthen the close ties with the working class.

The fifth part describes the practice of the Communist Party of Australia，including striving for and maintaining peace，actively participating in the parliamentary election campaign，actively participating and leading the trade union movement，actively protecting the rights of indigenous peoples，and focusing on handling relations with the Labour Party.

The sixth part mainly expounds the history，practice and theory of Communist Party of Australia（Marxist-Leninist）.

The seventh part evaluates the theory and practice of the Communist Party of Australia.First of all，this part explores the main reasons for the decline of Communist Party of Australia after the second world war that includes the suppression of bourgeoisie and its government，the impact of the major events of the international communist movement，many times splits and the decline of Australian workers movement and the trade union movement after the second world war.Secondly，this part analysizes the opportunities and challenges facing for the Communist Party of Australia.2008 international financial crisis and the breakthrough of Green Party in the Australian federal election in August 2010 brought a rare opportunity for the development of Communist Party of Australia.However，today Communist Party of Australia is still facing many serious challenges：the proliferation of reformism in Australia；Australian electoral system is a limit for small parties and Labour Party is a strong challenge；the mobility of the working class of Australia is increased，which is not conducive to the Communist Party of Australia to recruit party members and to strengthen party building；the majority of Australians believe in religion，which is not conducive to the spread of Marxism，and so on.

Keywords：Communist Party of Australia，development process，capitalist crisis，the Collapse of Soviet Union and East Europe，theory and practice