The asymmetric information between the commercial banks and the SMEs cause SMEs lose their faith after they get loans,making the commercial banks dare not to extend credit to SMEs.The phenomena and the restriction conditions were analyzed.The conclusions were drawn on the condition of the static state game, the behavior of SMEs were affected by the expectation of themselves and the commercial banks. On the condition of once dynamic game, SMEs would lose their faith. On the condition of unlimited game, keeping their faith was the best choice of SMEs. Collecting the faith files of SMEs and adopting the post-punishment regulation would be the good ways.