The invention relates to an autonomous target ranging method of an unmanned aerial vehicle. Autonomous ranging can be conducted on a to-be-tested target at multiple angles, yaw and pitching motions ofa pan-tilt are controlled by a main control module, thus a laser range finder aligns and ranges the target automatically, the process is completely autonomic, and a target is aligned without manuallyoperating the laser range finder. Under the condition that the unmanned aerial vehicle ranges the moving target, the condition of target missing is further considered in the autonomous target rangingmethod of the unmanned aerial vehicle, the missing direction of the target is detected by the main control module, thus the pan-tilt is controlled to do yaw and pitching motions in the target missingdirection, the probability of the tested target recaptured by a camera is increased, and thus the successful rate of ranging the moving target by unmanned aerial vehicle airborne equipment is increased.