Infrared radiation characteristic measurement is one of the fundamental technologies for obtaining target infrared radiation characteristics, target infrared detection and recognition, and target infrared stealth evaluation. The rapid development of new offensive and defensive technologies requires infrared radiation measurement system to develop direction of large aperture, high dynamic, and high precision. Infrared radiation measurement accuracy of the system is affected by many factors such as environmental temperature, calibration error, atmospheric correction error, and detector stability. How to perform high-precision large aperture and high dynamic calibration on the measurement system, and how to compensate for the impact of environmental temperature changes on measurement accuracy are urgent technical difficulties that need to be solved. Therefore, based on the distributed reference cascade calibration, Aiming at the influence of external environment on measuring system temperature, the differential model of system thermal radiation is proposed to suppress the influence of system temperature change, improve the calibration accuracy, measurement accuracy, and environmental temperature adaptability of the calibration results.This paper takes the distributed reference cascaded calibration method as the basis, analyzes the mechanism of the calibration error and measurement error caused by temperature change in the infrared radiation measurement system, and establishes a simple and feasible system thermal radiation differential model. Based on the uniform background with known radiation quantity, the system thermal radiation is differentiated during the calibration and measurement process to suppress the influence of system thermal radiation change on measurement accuracy. Based on a 450 mm aperture radiation measurement system, relevant experiments are conducted to verify the high dynamic measurement accuracy under different environmental temperatures.In response to the demand for large aperture, high dynamic range, and high-precision infrared radiation measurement, a distributed reference cascade calibration method is used as the basis to analyze the mechanism of radiation measurement errors caused by changes in external environment or calibration light source temperature. A system thermal radiation differential model is proposed, which does not require complex model calculations of the system's own thermal radiation or complex experiments to establish the relationship between system temperature and grayscale drift. High precision measurement can be achieved without increasing the complexity of the system structure. After adopting the model, the radiation calibration error was reduced from 9.81% to 1.58%, and the radiation measurement error was reduced from 96.46% to 4.34% under different environmental temperature differences. This effectively reduces the measurement errors caused by rapid changes in local temperature due to external calibration light sources and overall temperature changes due to environmental temperature, improves the calibration accuracy and measurement accuracy of large aperture infrared radiation measurement systems, expands the temperature adaptability range of the calibration coefficient, and reduces the calibration frequency. In addition, this model has a better suppression effect on low radiation levels and has a natural advantage in measuring weak targets at long distances in external fields.This paper, based on the theory of infrared radiation characteristic measurement, conducts an in-depth analysis of the principle of distributed reference cascaded calibration method, and then analyzes the mechanisms of radiation measurement errors caused by changes in environmental temperature and the calibration light source. A simple and feasible system thermal radiation differential model is proposed. Based on the model presented in this article, multiple experiments were conducted using a radiation measurement system with a 450 mm aperture in both laboratory and outdoor environments at different temperatures. The experimental results show that the model can effectively improve the calibration accuracy, measurement accuracy, and environmental temperature adaptability of the calibration coefficient by using only a uniform background with known radiation, and has good feasibility and applicability.