Discourse markers ?“Zhebu” and“Nabu”in the spoken language or the discourse, which is from “Zhe bu shi ma？”、“Na bu shi ma？”to reduce the formation and the semantic grammaticalization. “zhebu”、“nabu” usually occurs in the middle of a speech turn, has the discourse function of proving by examples and explaining the result, “zhebu”、“nabu” occuring in the turn-opening has the discourse function making an explanation cause. As a discourse marker, “zhebu”“nabu”also has the pragmatic functions: identity function、explanation、emphatic function and the function of expressing the current things.