Abstract：In modern Chinese, "zhiyao(只要)" is a conditional conjunction and expresses the relationship of sufficient conditions."Zhiyao(只要)" first appeared in the Tang Dynasty literature,but its appearance is only temporary adverb"zhi(只)" and the verb "yao(要)".With the development of language,influenced by social and historical factors and the language internal factors—phememe,pragmatic,semantic,speech sound,"zhiyao(只要)" gradually becomes a conditional conjunction.