Abstract: The vernacular movement is a language reform movement which took place in China at the beginning of the 20th century, aiming at replacing classical Chinese with vernacular as the common written language. The development of the vernacular movement in Tsinghua school can be divided into four stages:the beginning, the slow development, the dispute between classical Chinese and vernacular, the victory and the detour. The vernacular movement in Tsinghua School not only shows the students' diversified thinking on language problems, but also has great significance for the formation of the new poetry exploration road of the poetry group of Tsinghua Literary Club headed by WEN Yiduo and the New Moon Poetry School.