Because the extra-low-altitude missile works in the background of sea clutter, its fuse signal will be jammed easily. Nevertheless, the traditional signal processing methods behave badly. Wavelet transform has the multi-resolution rate characteristic, which can filter the noises in the clutter signal and improve the precision of the fuse machine, therefore the real object will be identified according to the echo frequency. The simulation in this paper was based on the testing data of radar fuses. And the results indicated that after the fourth-order wavelet decomposition, this algorithm could effectively filter most of the noises. So that it can promote the anti-sea-clutter-interference capacity of the extra-low- altitude radar fuse and the kill probability of the missile.