The subject of this dissertation is Russell's logical atomism，and the major issues discussed here are his two kinds of standpoints on the structure of world and the relation between them.Logical atomism is a theory about the fundamental structure of reality，which is set up by Russell when using the method of logical analysis to resolve the traditional problems of philosophy during the originating phase of analytical philosophy.This theory belongs to the main tradition of western metaphysics，but differs from the tradition in the way that Russell arrives at the fundamental structure of world from the essential structure of language.

The central claim of logical atomism is that the world can be analyzed into aplurality of independently existing logical atoms that cannot be broken down any further，and these atoms exist in the complex structures of facts，i.e.they exhibit certain qualities or stand in certain relations.The doctrine shows that there are two kinds of ultimate ontological constituents of world：logical atoms and facts.Compared to the theory of traditional metaphysics，one distinctive feature of Russell's logical atomism is that he commits a particular object——facts，but his opinion of the sorts of facts and their logical form isn't as extreme as that of early Wittgenstein.Besides atomic facts，he also acknowledges negative facts，general facts and belief facts，although he accepts early Wittgenstein's the principle of extensionality and denies the existence of these facts in his later philosophy.

Another distinction of logical atomism is his definition of logical atoms.Logical atoms can be acquainted，which is different from both the traditional individuals or substance and early Wittgenstein's objects.Logical atoms include three kinds of things：particulars，qualities and relations.Russell holds the substratum theory and realism to themin the period of logical atomism，but in his later philosophy he turns to the bundle theory and realism.

Russell's points of view on facts and logical atoms frame his theory of the structures of facts of world.He acknowledges only the reality of logical atoms and facts，and common objects and physical objects usually regarded as reality are apparently complex and single entities，which haven't the reality in isolation，and are the logical constructions from sense-data，i.e.the series of classes of sense-data.Russell's theory of logical construction on physical objects is his doctrine of the structures of series of world.

The theory of the structures of facts of world and the theory of logical construction of physical objects are Russell's two kinds of structures of world——the structures of facts and the structures of series.The connecting point between the two kinds of structures of world is his direct equation particulars which are one kind of logical atoms with simple sense-data.According to one of two arguments which William Lycan provides to equate logical atoms with ontological atoms，this equation isn't successful.In addition，the two kinds of structures of world seem to show that，for one thing，logical atoms can't exist independently and must be in various kinds of complex structures of facts，for another thing，they can exist side by side separated from facts，and generate the series of classes according to the relation of compresence，i.e.constructing physical objects.Then，which kind of structure is more fundamental for logical atoms？

Russell hasn't definitely distinguished the two kinds of structures of world，so he can't deal with this problem.In the light of his only one text evidence and his wholly philosophical position，the structure of facts must be more essential.In fact，Russell's facts and physical objects embody two kinds of complex which are early Wittgenstein's terminologies：logical complex and physical complex，and Wittgenstein prosposes that the latter is subordinate to the former.Russell's two points of view on the structure of world can be recognized as corresponding to Plantinga's space-time world or physical universe and the real world.

Key Words：fact logical atom logical construction sense-data