Chinese Treebank as a kind of valuable resource in Chinese Information Processing includes rich information on the sentence structure and the constitunent combination.A study on the combination of POS strings is the basic work for the effective use of treebank information.This paper investigates the ambiguous combination in Chinese Treebank,revealing that it largely requires semantic feature to resolve the ambiguous combination and structure in Chinese,and can not be solved simply by grammatical features(such as POS information) of words.