The semi-active missile is the important component of the air defense weapon system, with further guidance range, higher reliability as well as lower cost and less maintenance technical difficulty. Nowadays with the growing requirement for striking stealth targets, more radiation power of the guidance radar is required. In this situation,, the direct-wave signal spurious will severely affects the performance of system sensitivity. To solve this problem, a new method of direct-wave suppression based on spatial cancellation is first proposed. The simulation results show that the direct-wave which entered into echo channel can be suppressed adaptively. The tracking stability for stealth targets of semi-active seeker under intense radiation circumstance is improved obviously.