A novel high precision time-interval measurement method is proposed to improve the precision of pulsed laser ranging.Based on the pulse counting method,a temperature compensated crystal oscillator is used to generate synchronous sine wave reference signals of quantized timing pulses,and the improvement of precision of time-interval measurement is converted into phase estimation.The reference signals are sampled through the pseudo-nonuniform sampling method,and theoretical formulas are educed according to the pseudo-nonuniform sampling method in the paper.Afterwards,the least square method is used to fit the sampling data and pseudo-nonuniform sampling signals are reverted into sampled reference signals to fulfill phase estimation.Then high precision time-interval measurement can be realized.The method is used in a pulsed laser ranger for testing,and ranging precision is better than ±5 mm.