Abstract: The solar simulator is currently the mainstream equipment for testing the I-V characteristics of PV modules. However,there are differences between its spectral irradiance and the standard solar spectral（AM1.5G）irradiance,which is one of the main reasons for the deviation of test results. This paper analyzes the spectra of three solar simulators from the perspectives of spectral matching degree,spectral coverage（SPC）,and spectral deviation（SPD）. Combined with the spectral response characteristics of mainstream PV modules such as PERC,HJT,and TOPCon in the current market,the spectral mismatch factor is calculated to analyze the impact of spectra on the I-V characteristic test results of PV modules. The analysis results show that:1) The high or low I-V characteristic test results of PV modules are not related to the spectral matching degree level,but are determined by the spectral distribution at the difference between the spectral response of the reference device and the spectral response of the test sample. 2) Usually,the SPC of a solar simulator with A+ spectral matching degree level is close to 100%. When the spectral matching degree level is consistent,the deviation of the I-V characteristics of PV modules tested using a solar simulator with a smaller SPD,the resulting deviation is smaller. 3) To more accurately test the I-V characteristics of PV modules, it is recommended to use reference devices with the same spectral response as the sample,or perform spectral mismatch correction.