The ranging error of general optical rangefinder depends on the visual error and observation conditions of the operator. The visual error of the operator is related to the experience of the operator, such as the observation conditions and visibility, the clarity of the target contour, etc. And the error also increases with the increase of the measured distance. The accuracy of laser ranging is independent of the operator’s experience and the measured distance, and the error depends on the accuracy of the instrument. Laser ranging is easy to operate and fast. The laser rangefinder is small in size and light in weight. Because of its high frequency, lasers can emit extremely narrow beams without huge antennas. Laser rangefinder has strong anti-interference ability. But because of its high brightness and good directivity, laser can solve this problem well.