Abstract: In order to satisfy the requirements of developing low cost impulse correction munitions, the method of open loop correction is discussed. Based on a ballistic model, the relationship between corrected distance and the magnitude of impulse control force is studied, and relationship between the miss distance and the class number of impulse control force analyzed. Thus, according to the maximum dispersion distance and the allowable miss distance given, the magnitude and class numbers of impulse control force is selected. Simulation calculations with 8 classes of impulse control force were performed and the feasibility of open loop correction proved.