The famous deceased contemporary Chinese linguist Prof. Dai Yaojing from Fudan University was invited by School of Liberal Arts of Nanjing University to give anacademic speech, titled The Expression Methods of Chinese Sentence Complexification, at the “Academic Forum on Sentence Complexification Issues” (No.2) on November 24, 2011. The speech focuses on the expression methods of Chinese sentence complexification, involving two major aspects. One is the cooperative relationship between the complexity of the thought’s content and the complexity of the structure, that is, deep in and deep out, shallow in and shallow out, deep in and shallow out, shallow in and deep out (complicated thoughts with complicated structures, simple thoughts with simple structures, complicated thoughts with simple... structures, simple thoughts with complicated structures). The other is the types of complexification. From the perspective of three-level, there are syntactic expression, semantic expression and pragmatic expression. In addition, multilingual mixing can also complicate sentences. The syntactic expressions of the sentence complexification include complex sentence structures, long length, multiple levels, etc; Semantic expression is mainly the issue of ambiguity, including five kinds of ambiguity: phonetic ambiguity, lexical ambiguity, structural ambiguity, semantic ambiguity and pragmatic ambiguity; pragmatic expression refers to understanding the meaning of a sentence requires a combination of contexts at all levels.