For the problems of poor working environment and low efficiency in the grinding process of circumferential weld on inner wall of pipe, an automatic grinding control system based on industry robot was designed and implemented. The pipe was positioned by servo mechanism. Based on the calibration results of tool and workpiece coordinates, the robot grinding trajectory was automatically planned by off-line programming software. After the grinding process was simulated and verified in the offline programming software, the generated grinding trajectory code was downloaded to the robot control system to carry out the technological experiment. Through the grinding technological experiment, the basic technological parameters and the final process of automatic debugging were formed. For the automatic operation and detection, the overall network architecture of the control system was set up.