The purpose of the present study was probing into the effect of social prejudice and group threat as well as their cognitive processing mechanism on the intergroup conflict behavior conformation. Based on the interviewing of related literatures review and experiments, the present study operated the implicit social prejudice and intergroup threat as the independent variables, and choosing the index of Competitive Reaction Time task and Story Completion Protocol as the experimental dependent variables with choosing the Doctors-Patients prejudice as the exemplars of social prejudice. The present study found that as follows: (1) For DOCTOR subjects, social prejudice had the significant main effect on the punished intensity and punished duration as well as the aggressive expression number. But for PATIENT subjects，social prejudice had the significant main effect only on the punished duration index ; (2) Whether DOCTOR subjects or PATIENT subjects, group threat had the significant main effect on the punished intensity and punished duration and also the aggressive expression number. The result suggested that for the conformation of the intergroup conflict, according to the forces comparison which both sides of conflict hold, social prejudices played important role showing as Directional feature; and group threat had more prominent and direct impact on the trigger of intergroup conflict. In addition, the present study also found that the "two-direction" that research way helps to reveal the nature of the relationship of social prejudices and aggressive behavior.