Measure-word is one characteristic of Chinese and Sino-Tibetan. Its basic syntactic function is to categorize nouns, but some research shows its classification function is very weak in chinese. This paper takes the measure-word JIAN(件) as study subjects in order to discover the principle for the categorization of the measure-words. The paper on the basis of analyzing the etymology and the categorization of measure-word JIAN(件), to find out the reasons on the choice of nominal structures by this measure word.