Aiming at the problem of poor global applicability of the object image mapping model in the direct calibration method of structured light measurement system, this paper proposes a subarea calibration method based on the distortion model. First, the projection matrix of camera linear imaging is estimated by using Zhang Zhengyou's plane calibration rule. Then, the matrix as the initial value is taken to solve the camera distortion parameters by ordinary least square. Finally, the image subarea is divided according to the distribution law of distortion shift vector for calibration. The experimental results in the same scene show that compared with the global direct calibration method, the calibration accuracies of the method in X direction and Y direction are increased by 37.40% and 56.20%, respectively, and it has wide applicability in the field of structural light measurement.