Coordinate correction method of robot arm

The invention provides a coordinate correction method of a robot arm. The coordinate correction method comprises the following steps: (a) when the robot arm operates in a working space, controlling the robot arm to move according to a movement command, and acquiring a reference positioning point reached by the robot arm by using a three-dimensional measuring device; (b) obtaining a reference coordinate system according to the reference positioning point; (c) making the robot arm leave the working space, when the robot arm returns to the working space to operate, controlling the robot arm to move according to the movement command, and using the three-dimensional measuring device for obtaining an actual positioning point where the robot arm reaches; (d) obtaining an actual coordinate system according to the actual positioning point, and calculating to obtain coordinate correction information according to the reference coordinate system and the actual coordinate system; and (e) adjusting the robot arm according