Abstract: Wittgenstein is a philosopher of language， and his philosophy is often divided into the two parts of his early and later philosophies. Different from others， although both are language-centered， his early and later philosophies are of completely opposite positions in having disclosed utterly different worlds of language. Accdemically， everyday language is considered meaningless and is taken as the source of chaos in his early philosophy， while it is not only meaningful but also the only academic choice in his later philosophy. The early one is prescriptive in ideally prescribing language by logic. Logic decides the meaning of language. In his later philosophy， language use decides and is meaning， and the actual use of everyday language is entirely accepted with an attitude similar to what is rational is actual and what is actual is rational. Meaning of language depends on the actual use and what explanation and understanding given by language users. Meaning in the world of everyday language is ultimately determined by language understanding.

Key words: Wittgenstein, world of language, meaning, logic, language understanding