The invention relates to an industrial robot base coordinate measuring method, which comprises the following steps: setting a robot base coordinate system to be OBXBYBZB, a robot tail-end flange coordinate system to be OTXTYTZT, and a measurement coordinate system carried with a laser tracker to be OMXMYMZM; arranging a target ball in the center of a flange at the tail end of a robot, and ensuring the target ball does not shift in the robot motion process; keeping other shafts of the robot immobile, only enabling a first shaft to rotate, and carrying out fitting on a plurality of point location data obtained after continuous rotation to obtain a circle, the normal vector of the circle being Z-axis direction of the base coordinate system; placing the target ball at a plurality of places in a robot base plane, measuring multiple points and obtaining a robot base plane equation through data fitting, the point obtained when the normal vector obtained through fitting in the step above meets the robot base plane being an original point OB of the base coordinate system, and thus a coordinate axis ZB can be obtained; controlling a second shaft of the robot to be in single axis motion, placing the target ball at some fixed place of the second shaft, continuously rotating for a plurality of point positions and carrying out fitting on the recorded points data to obtain a plane, projection of the plane to the base plane being the coordinate axis XB; and through a right-hand rule: ZB=XB*YB, obtaining the coordinate axis YB.