The invention discloses a robot tail end actuator position error measuring method, belongs to the field of industrial robots, and provides a method for obtaining the position information of an accessory at the working position of a tail end actuator through a camera image shooting method. The method is characterized by including the steps of driving an industrial robot to arrive at different positions of an operation area, and analyzing and calculating the positions of needle point images and calibration target graphs in a camera to obtain the position error of the industrial robot. Accordingto the method, the size and placement position of a calibration target can be designed according to the actual target working area, and high flexibility is achieved; the calibration operation can be carried out only with the industrial camera and other machine visual matching devices, and a calibration system is simple.