A high-precision time-of-flight interval measurement technology based-on multi-point average principle method for pulsed laser range finder has been presented. This method refers sine signals as the measurement benchmark, on the basis of pulse counting method, the sine signal time has been high-precision subdivided with the principle of multi-point average method to eliminate time cumulative error caused by nonlinear sine curves. The high-precision pulsed laser ranging system has been built, pseudorandom sampling for the reference sine signals in a cycle by using linear frequency modulation technique to achieve high-precision time interval measurement. The structure of ranging system is simple and low cost. The single distance measurement accuracy obtained by experiments is stable within ±3 mm.