In Chinese teaching for foreign students, comparative sentence “Bi” is a quite important sentence pattern. However, foreign students easily make mistakes of this even when are in higher grade. Usually they do not know how to use the negative pattern of the comparative sentence properly. Thus, this thesis is going to analyze the reasons, and specifically divide the negative pattern into three different patterns and respectively explain and compare the meaning of them in detail from the perspective of presupposition, at the same time suggest ad...