Polishing is an effective process method to improve the surface quality of aero-engine blade. The clamping error between fixture and blade leads to position error of blade surface and reduces processing quality. In this paper, a laser calibration system and a calibration algorithm are proposed to compensate clamping error. Firstly, theoretical point data of blade surface is obtained from CAD model, and the measurement point data of blade surface is obtained through laser sensor. A modified ICP algorithm is designed to calculate the coordinate transformation between the theoretical points and the measurement points. Secondly, Bezier surface is introduced to evaluate the calibration accuracy based on the distance between fitting surfaces rather than points. Finally, the point cloud registration is optimized by particle swarm optimization (PSO) algorithm based on the Bezier surface evaluation. The calibration algorithm combined ICP algorithm, Bezier surface evaluation and PSO algorithm to realize clamping error compensation. The quality of polished blade surface is consequently improved.