High-precision pulsed laser ranging system is always one of the hot topics in the field of laser ranging finder. The existence of ranging error has a direct impact on the results of laser ranging accuracy. The study of differential signal moment discrimination has not been reported. Therefore, it is of great significance to study the differential time discrimination method. The factors affecting the accuracy of pulsed laser ranging were analyzed. It was considered that the time jitter caused by the amplitude-time swimming effect and the rise-time swimming effect was the most dominant factor affecting the ranging accuracy. It can be seen from the analysis that the differential signal time discrimination circuit designed can effectively improve the ranging accuracy and meet the design requirements. In the experiment, the single-distance measurement errors of different distances (<70 m) were kept within 9 mm by the differential signal time discrimination circuit. The single-end signal time discrimination circuit had a single range accuracy ranging from [-12 mm, 11 mm]. Compared with the single-end signal single-distance measurement error, the ranging accuracy is significantly improved. This method can provide reference value for how to improve the accuracy of pulsed laser ranging technology.