Array detection technology is of great significance to the laser ranging system for space debris with extremely weak echo signals, because array detection technology can improve the probability of detection success in laser ranging of space targets. Focusing on this new laser ranging technology, the preprocessing method of laser ranging data based on array detection technology was researched in this paper. The research was based on general preprocessing method of satellite laser ranging data. According to the characteristics of the array of Superconducting Nanowire Single Photon Detector (SNSPD), together with the methods of ground target measurement and the methods of multi-peak Gaussian fitting & cross correlation analysis, the time offset correction between channels of the multi-channel laser ranging data was realized. Poisson statistical analysis and cyclic fitting filter were used to realize signals automatic identification and data fitting of multi-channel laser ranging data, etc. At present, this data preprocessing method has been successfully applied in the experiment of 4 × 4 array laser ranging experiment platform of Yunnan Observatory, Chinese Academy of Sciences, this method can correct the time offset between channels of multi-channel laser ranging data, and the application of this data preprocessing method has achieved good results.