Space debris detection using superconducting nanowire single-photon detector (SSPD) as detectors is proposed and both theoretically and equivalent experimentally verified. The multi-detection characteristic of SSPD during gating period is analyzed, and the signal noise ratio (SNR) model with echo photon number is established. Effects of laser repetition rate, sky background noise rate and dark count rate of SSPD on SNR are discussed. Taking the kHz laser ranging system of Yunnan Observatories as an example, combined with the echo photon number equation, it implies that the kHz laser ranging system at Yunnan Observatories has the capability for 1 m2 space debris detection from 830 km away. Considering the fiber coupling requirement, an experimental curve of SNR versus echo number is obtained, which verifies the proposed method. Both theoretical and experimental results show that SSPD has the potential for space debris laser ranging.