摘要：The core ideas of Constructivism were mentioned by John Dewey, so it is not a new idea. Constructivism claims that each learner constructs knowledge individually and socially. The ＂glue＂ that holds the constructs together is meaning. Knowledge is not ＂out there＂, as the realist philosophers such as Plato claimed. Knowledge is always an interpretation of reality, not a ＂true＂ representation of it. Thus, the aims of this study are： （1） to shed the light on the schools of constructivism, and （2） to clarify the principles of the constructivist learning in general and in language teaching in particular.