Introduces in brief the principle of three kinds pseudo-random code fuzes, viz. the pseudo-random code phase modulation fuze, the pseudo-random code phase modulation and pulse amplitude modulation(PAM) combined fuze, and the pseudo-random code phase modulation and random(pseudo-random) pulse position modulation(PPM) combined fuze. On this basis, their SNR gains in signal processing after band pass filter to the correlation detection, and the overall SNR gains of the whole procedure after correlation detection are deduced in detail. The results show that the latter two kinds of fuzes have the same performances concerning antinoise that are stronger than that of the pseudo-random code phase modulation fuze.