Abstract: At present, the ambiguity in the implementation of the part-of-speech tagging of Chinese dictionary is large and strongly random. By comparing the numbers, parts of speech system and POS(parts of speech) tagging styles of the two largest dictionary——The Contemporary Chinese Dictionary and The Modern Chinese Standard Dictionary, we found that there are some differences in the speech tagging styles among the same words in above mentioned dictionaries, and the reasons of leading to the differences. And the reasons may benefit to the writing and standardization of dictionaries