The performance of pulsed laser ranging is directly influenced by the method how to measure the time-interval. Refer to the idea of interpolation time-interval measurement, the character of triangle reference signal is used to realize measurement on time-interval which has advantages of long measurement range and high precision. The principle how to use triangle reference signal to realize measurement on time-interval is described. The factors that affect the precision of time-interval measurement is quantitatively analyzed. It is pointed out that the frequency of triangle reference signal and the noise attached in triangle reference signal are the two main factors which affect the precision of time-interval measurement. Then, their affect on the precision of time-interval measurement is numerically simulated. A confirmatory experiment is designed to explain how the noise attached in triangle reference signal affects the precision of time-interval measurement. Both the numerical simulation and the experimental result show that the method of measurement on time-interval in pulsed laser ranging which uses low frequency triangle reference signal can achieve high precision. Besides, both improving the frequency of triangle reference signal and reducing the noise attached in triangle reference signal can effectively improve the precision of time-interval measurement.The numerical simulation and experimental results also confirm the feasibility of measurement on time-interval on pulsed laser ranging.