Language planning focuses are prevalent in all aspects of the practical use of language, and language planning and policycan play a greater role for a pluricentric language as a result of a political rift. When it comes to languages in Mainland China and Taiwan, all linguistic institutions should be concerned and the vocabulary is an apparent necessity in language planning. In this study, taking thetwo predominant dictionaries as an example, we endeavor to examine the discrepancies seen in the two polities with the aim ofrevealing the sociopolitical realities accounting for the inclusion and exclusion of certain vocabulary in the Modern Chinese Dictionaryin Mainland China (Xiandai Hanyu Cidian, 1996, 3rd edition) and the New Version Dictionary of Media Language in Taiwan (XinbianGuoyu Ribao Cidian, 2000 edition). In conclusion, we argue that various types of discrepancies pose an obvious obstacle in the relationship between the Mainland and Taiwan, therefore, a collaborative planning effort seems necessary in order to facilitate communicationbetween the two polities.