Grammaticalization is always an important topic in Syntax. The grammaticalization of verbs or adjectives will produce new syntactic categories, such as verbal aspects. This paper focuses on QUE and discusses the process of its grammaticalization, the periods in which its grammaticalization began and finished, and the factors influencing the transitions. The data used in this paper are mainly the Buddhist Scripture of Liuchao, and other data, which are not the Buddhist Scripture, are also referred to. The discussion begins at the comparison of ”QUE+V” and ”V+QUE” and the discussion of ”V+ QUE” is the main point. ”V+ QUE” lost its lexical meanings gradually because of the change of its syntactic positions. ”V+QUE” changed from serial verb to causative verb and is placed after the Object. In Liuchao, QUE prototypically didn't carry an Object when it was a resultative complement. The grammaticalization of QUE finished in the Tang Dynasty, in which the V of ”V+QUE” was not limited and ”V+QUE” could carry an Object. These issues are the main points investigated in this paper.