Abstract: There is still a debate whether there exists a case system or not in mandarin Chinese.The negative proposal encounters methodological deficiencies in language studies:on the one hand it establishes "universal"criteria based on a specific language;on the other,it lays emphasis on static investigations and ignores dynamic studies,which casts doubt on the validity and reliability of the researches.To make up for these deficiencies,this paper adopts a dynamic approach in the current research.Based on Chinese dialects and classical Chinese as well as theoretical reasoning,the conclusion that Chinese is case marked is made.Different from those languages with rich inflectional forms,mandarin Chinese does not realize its case morphologically and phonetic realization is the necessary and sufficient condition for its case realization.