In recent years, many positive factors (such as the cultivation of the market environment, the policy support, etc) have provided good development space for e-commerce. As a new mode of e-commerce, online group buying originated from American Groupon. But many problems have already exposed with its rapid development, such as the good and bad group buying websites being intermingled, the seller’s fraud operation, no guarantee after sales, and the consumer’s difficulty to maintain his right, etc. In this paper we first generalize the interests that online group buying brings to all the industry chain subjects. Then according to those exposed credit problems, we first analyze an individual seller’s behavior on the market using static game analysis and find out factors influencing the game subjects’ strategy choosing; then discuss the whole market’s gaming behavior using the dynamic game with imperfect information and find out its perfect Bayesian equilibrium by the backwards induction method. At last we put forward some measures to solving existing problems.