In the measurement of radiation characteristics, the selection of integration time of infrared camera is an important factor affecting the accuracy of characteristic measurement. To solve this problem, the infrared image contrast, image signal-to-noise ratio and radiation characteristics measurement accuracy under the same temperature and different integration time are analyzed in this paper based on the experimental data of radiation characteristics measurement. The analysis results show that the integration time affects the measurement accuracy of radiation characteristics by affecting the contrast and signal-to-noise ratio of infrared image. Appropriately improving the integration time of infrared camera can enhance the contrast and signal-to-noise ratio of image, so as to improve the measurement accuracy of radiation characteristics. The results have guiding significance for the selection of camera integration time of infrared radiation characteristic measurement system.