Abstract: Synthesis of the error in simulation test is the important approach to judge accuracy and credence of simulation.Based on the Monte Carlo method,a kind of synthesis method of the error is proposed,which can be used in ground simulation test of docking mechanism implemented on the half physical synthetic simulation test bed of docking mechanism.Moreover,the statistic law of ground simulation result of docking mechanism is obtained.The confidence coefficient and the confidence interval of simulation result are given by volume simulation.The criterion for appraising accuracy and credibility of simulation results is suggested.