In order to solve the problem that the results from the traditional method for kill probability are larger than the real results in approval test for the burst firing antiaircraft gun, based on the angle error time series, the angle error was converted to distance error on the plane which was vertical to the line between the gun and the target; the error projection function was established to project the distance error on the vertical plane to distance error on the three sections of the target; combination with the above error projection and the three section graph of the target, a calculate method for kill probability of burst firing antiaircraft gun based on error projection was proposed. The simulation results and the real results from the approval test show that the method in this paper is more suitable to represent the actual performance of the weapon than traditional method.