The factors affecting ranging precision were analyzed firstly.It is considered that increasing the frequency of the time-measuring counter,using fast circuit,abbreviating the laser rising edge and improving the signal to noise ratio can improve the precision of laser ranging while abbreviating the laser rising edge is the most effective way.After that,a high precision pulsed laser ranging equipment was designed based on a 1.2 ns ultra narrow pulsed laser.Test result show that the single point ranging precision was less than 1.2 cm.