Based on a simplified evolutionary game model, this article analyzes the internal mechanism of credit cheating behaviors in E-Commerce business. With regard to potentially technological or rule defaults in credit system as well as traders’ selfish rationality, presence of credit cheating is to some extent unavoidable. We then suggest a new kind of credit system, which is independently coexistent with traders and trading, should be set up to control credit cheating. Simulation experiments support the ideas aforementioned.