Abstract: In the traditional English language teaching, summative assessment is widely adapted and accepted. However, this assessment method is neither scientific nor reasonable. Both language teaching and learning are a process,the result of which can not be evaluated through one or two tests, especially for oral English teaching and learning. Formative assessment is a form of testing that requires students to perform a task. The paper studies the meaning, the purposes and the principles of formative assessment, and proposes the model and the ways of applying formative assessment in college oral English classes.