Abstract: Nowadays, the infrared imaging technology is widely used in space detection, land inspection, security monitoring and other fields. In order to ensure the accuracy of the infrared target recognition, it is necessary to completely understand the radiation characteristics of the target. The target radiation characteristics need to be measured in out-field condition, and the large area blackbody radiation source need to be used for field radiation parameters calibration to the measuring equipment of target characteristics. A large area blackbody radiation source was designed. The radiator was made of aluminum material with black treatment, and the proportion integral differential (PID) control algorithm was adopted by the temperature control of large area blackbody radiation source. When the actual ambient temperature was 26.8 ℃ and the humidity was 60%, the radiation parameters of the target characteristics measuring equipment were calibrated. The test data show that the uncertainty of the radiation temperature measurement is 0.4 ℃ ( k = 2), and good application effect is achieved.