Abstract: Aimed at the hypersonic interception combat demand caused by the rapid developments of the near space vehicles, a suboptimal midcourse trajectory modification algorithm was designed based on model predictive static programming(MPSP).Firstly, analyzing the optimum conditions at the handover moment between the midcourse and terminal guidance, the zeroing effort interception condition was deduced according as the interceptor and target velocity ratio and their velocity heading angles. Secondly, introducing the proportional navigation as the terminal guidance law, the capture region of the terminal guidance was analyzed for the cases where the interceptor failed to satisfy the zeroing effort interception condition. The structure of the capture region was built in the plane composed of the interceptor and target velocity heading angles, serving as the constraints for the interceptor at handover moment. Thirdly, the Gauss pseudospectral method (GPM) was used to get the nominal optimal trajectory, satisfying the zeroing effort interception condition and the MPSP was introduced to modify the trajectory, considering the capture region constraints. Finally, the simulations were carried out to testify the rationality and effectiveness of the proposed method.