The maximum range of a laser range finder has been tested by measuring the extinction ratio outdoors and the time-sequence gain coefficient ratio indoors. Other major parameters, such as ranging accuracy, gating range, gating accuracy, range resolution, were tested using an indoor system composed of an electronic delayer, two laser source simulators, a variable optic attenuator, and a computer. The principle of the measuring methods is discussed and the measured results are analyzed. The experimental results prove the validity of these measuring methods.