Aiming at HTV2 （hypersonic technology vehicle 2） targets with high speed and high maneuverability， the midcourse guidance of interceptor missile using hit-to-kill intercept strategy is studied， and a midcourse guidance algorithm based on trajectory tracking and prediction is presented. An adaptive grid interactive multi-mode （AGIMM） filter is used to track the target trajectory stably. The least square method based on forgetting factor is used to predict the trajectory of the target， and the motion state at the predicted handover point is obtained. The target state variables at the predicted handover point are used as midcourse guidance constraint， and the optimal midcourse guidance law is calculated by Gaussian pseudo-spectral method. The interception simulation of HTV2 target is carried out using the proposed midcourse guidance algorithm， and the simulation results prove the effectiveness of the algorithm.