Abstract: The temperature distribution model of thermal insulated pressure vessel was established. The effect of the environmental factors, thermal incentive intensity and were studied thermal incentive time to the test was analyzed. The influencing factors about detection of pressure vessel defects by using computational fluid dynamics software Fluent and infrared detection experiments. The results showed that: When the radiation temperature is below 300 ℃, increasing the thermal excitation will reduce the maximum contrast temperature. Whereas when it is higher than 300 ℃, increasing the thermal excitation will increase the maximum contrast temperature. With the thermal incentive time increasing, the trend of maximum contrast temperature rises first and falls later and the minimum contrast temperature appears in stable state. The influence of wind speed and surface blackness in environmental factors for the accuracy of testing experiment is severer. The influence of the environmental temperature can be ignored.