A dual threshold leading edge timing discrimination method for pulsed laser ranging is presented. The timing error caused by the amplitude variation of the received pulse is analyzed. The dual threshold leading edge timing discrimination method is used to generate a stop signal for flight time measurement and a time point signal related to the pulse amplitude. A high-precision interval measuring chip is used to measure the actual flight time of the laser pulse and the time interval related to the pulse amplitude and is also used to compensate the drift error caused by the timing discriminator. As a result, the ranging precision of $\pm$3cm is obtained. Compared with other timing discrimination methods, this method has the features of no AGC unit, simple circuit structure and wide dynamic range. Moreover, it can still compensate the drift error even when the pulse amplitude is saturated.