In modern society, “無所謂”, “沒關系” and “隨便” are widely used to express feelings and feelings. But these words overlap in semantics. In teaching, I find that Korean students often find it difficult to distinguish their semantic differences. I think there are two main reasons: one is the lack of function of textbooks and the inaccuracy of online dictionaries, which are the direct obstacles affecting students' learning effect, the other is the limitations of traditional teaching methods, which are indirect obstacles affecting students' learning effect. This paper first makes a comparative analysis of the semantic plane of the three words: through the reference books used by native speakers of Chinese, Chinese textbooks used by Chinese learners (several sets) and the classification of network dictionaries, it examines the semantic interpretation of “無所謂”, “沒關系” and “隨便”. Then it compares the semantic interpretation of the three types of materials, and finds out the problems existing in Chinese textbooks and network dictionaries. Then it makes a contrastive analysis of the three words on the pragmatic plane: in BCC corpus, it retrieves “無所謂”, “沒關系”, “隨便”, and sums up the pragmatic functions of the three words through the analysis of examples. Then the pragmatic functions of the three are compared to determine their similarities and differences. Finally, according to the analysis results, the teaching plan is designed, hoping to provide a reference for Chinese learners and Chinese teaching workers.