In modern Chinese, “bu” and “mei” are both frequently used negatives. Although “bu” and “mei” are synonyms of negation, but they are quite different in practical language. The study of “bu” and “mei” has been deepening in recent years, but most of them discuss the difference between “bu” and “mei” from the perspective of time limitation and subjective and objective. It holds that “bu” is limited to denying the present and future events, and that it denies the subjective will, the speaker’s subjective evaluation and knowledge, and is used for subjective will. “mei” is limited to negating what happened in the past and the present, negating objective facts and objective narration. Although there are some connections between these two perspectives, but they are not enough to fully explain the contradictory features of “bu” and “mei”. There are still many unexplained linguistic phenomena, so there are many difficulties in teaching. Therefore, this paper starts with the research errors of “bu” and “mei”, and explains them from the two aspects of typical usage and atypical usage, so as to make a clearer distinction between their different usages, so that students are not easy to confuse and misuse in the teaching process.