To ensure the accuracy of observation data, it is necessary to establish a comprehensive test system for radiation instruments, so as to test performance indexes. According to the provisions of WMO and ISO 9060, on the basis of verification regulations of pyranometers, experiments and researches have been conducted in zero offset, resolution, direction response, non linear error, and other performances indexes. Compared with thermal pyranometers, photoelectric pyranometers have significant spectral selectivity, and there are also other differences in spectral range, response time, measurement principles and structural materials. Therefore, their test methods are different. In the non linearity response test, the traditional solar simulator was replaced by the dual light superposition method. The study shows that it is advantageous to use the directional responses to indicate instrument’s performances in all directions and standardize the pyranometer’s classification than to use cosine errors and azimuth errors.