The security of both technical and trade credit factors becomes a serious bottleneck that affects the current development of e-business. Honest behavior is one of the important aspects of trade credit safety. It is a vital step to establish and maintain a safe credit system. In this paper, we analyze the characteristic of the credit in e-business and establish a motivation model that violates honest behavior in e-business. We evaluate the credit, the mode of evaluation and the behavior of the credit in e-business by using game theory. We present the factors that affect the justness of credit evaluation in e-business.