The invention relates to a method for evaluating the thermoelectric performance of a low-power concentrating photovoltaic-thermal system, a single reflection compound parabolic concentrator can collect solar scattered radiation with the efficiency of a geometric concentrating ratio reciprocal thereof in allusion to a low concentrating ratio range with the geometric concentrating ratio being less than 10*, the product of the geometric concentrating ratio reciprocal of the single reflection compound parabolic concentrator and the solar scattered irradiance is introduced into an electrical performance evaluation system, thereby realizing more accurate evaluation for the electrical performance of a device. In addition, a solar pyranometer and a scattered radiometer are installed in the device, and follow a tracking strategy of the device. Thermoelectric performance evaluation can also be realized for devices with a single-axis and double-axis tracking strategy accurately because the cosine loss is very small.