To improve the precision and credibility of infrared guidance hardwave in loop(HWIL) simulation test, the system error of infrared guidance HWIL simulation was studied and analyzed. The main error source of infrared guidance HWIL simulation system and mechanism was analyzed in detail, the guidance HWIL simulation model and the system error model were established from the perspective of the simulation mechanism. Based on the comparison and analysis on the missile trajectory calculating result with or without the loading error model, the influence of various error sources on the simulation test accuracy was analyzed quantitatively. The simulation analysis shows that the error of turntable mechanical and performance have little impact on precision of simulation test and can be ignored, and the effect of infrared seeker axial position error is obvious, needs to be addressed in the process of simulation test and to ensure that within a certain error range.