A simple variable-included-angle plane grating monochromator(VAPGM) has been installed in Shanghai Synchrotron Radiation Facility(SSRF).High accuracy of this monochromator is needed under the ultra-high vacuum environment.Measurement and calibration are very important.The rotation-angle-accuracy measurement,repeatability of the light spot transversal shift and the grating switching mechanism are investigated by auto-collimation method in this paper.The performance of the VAPGM is successfully ac...