By analyzing the disadvantages of the existing grinding technology of casting blank, a new process plan was put forward. In this plan, the 3D reconstruction casting model was scanned automatically to obtain the 3D point cloud data of the workpiece, and then the path was automatically planned according to the grinding process and offline programming was carried out to obtain the robot motion program. Finally, the casting grinding was completed automatically according to the process path. Based on the comprehensive consideration of cost, function, mechanics and interference, the overall layout of the grinding equipment was determined, and the special constant force grinding mechanism, vision system and other key components were designed and described in detail. Using existing mechanical equipment, industrial camera and line laser vision system to reconstruct the threedimensional model of the experimental workpiece, the results show that the size accuracy of the model is within ±01 mm, and the scanning speed is 1 000 mm/min. The grinding experiment shows that the surface roughness of the workpiece after grinding is less than Ra 63 μm, and the whole grinding surface flatness also meets the detection needs. The grinding efficiency of single equipment is about 10 times of that of manual.