Infrared detectors are the core components of infrared systems. In recent years, high sensitivity and low noise have become one of the research hotspots in infrared detector technology. For low-noise detectors with noise equivalent temperature difference (NETD) value less than 1 mK, the impact of environmental factors on their performance can not be ignored. The influence of test environment on the test results of sub-mK infrared detectors was analyzed from the aspects of blackbody temperature control accuracy, test environment temperature and airflow disturbance in the test environment. The test methods of low-noise infrared detectors were explored. The experimental results show that the accuracy of blackbody temperature control has a direct impact on the NETD value of high-sensitivity infrared detectors. The test environment temperature and airflow disturbance can affect the stability of blackbody temperature control, thereby indirectly affecting the accuracy of NETD value measurement.