Due to a variety of disturbances, trajectory correction projectiles can not detect real-time parameters resulting in the loss of correcting. Based on trajectory solution to meet the need of GPS/INS trajectory correction projectiles, this paper designs a muti-function setting system The system uses TI’s DSP as the CPU, achieving the function of human-computer interaction, data transceiver and shooting metadata storage. Based on the particle trajectory model, it uses the Newton interpolation to fit the relationship between the correction range and the start time of the damper, then uses difference coefficient and dichontomy to calculate the start time of damper. The real ammunition tests show that the fitter is stable and convenient, and can improve the missing success rate of correction obviously.