The laser ranging systems based on SNSPD and SPAD detectors are compared by experiments. In the experiments, the sky light background can be ignored when the receive echo is attenuated to 120 dB, the detection probability of SPAD is less than 0.2%, while the detection probability of SNSPD is 35%. When the laser emission frequency is below 1 kHz, the detection probability of SNSPD is more than 60% higher than that of SPAD. The study shows that the detection performance of SNSPD is much better than that of SPAD when detecting the weak signal echo photons. The reason is that SNSPD has lower dark counts and higher detection probability. At the same time, with no attenuation at the receiving end, the sky light background will bring dark counts, affecting the signal-to-noise ratio of the ranging system. Simulation analysis shows that the signal-to-noise ratio of the SNSPD-based laser ranging system is lower than 6 when the background luminance is higher than 30 W/(m2·sr), which may affect the stability detection of the laser ranging system.