The work aims to study the influence of the infrared sensor method WVTR tester improvement on the moisture permeability of packaging materials and the enhancing effect of the application performance. The temperature control technology and sample clamping device of the WVTR tester were improved so that the test temperature remained stable in testing process and the tester could test film/sheeting and container samples. By referring to the basic method (cup method) WVTR tester, the water vapor transmission rate of six different levels of permeable materials including 1.2 mm leather, 25 μm PET film, 230 μm solar back sheet, 20 μm PP film, 100 μm PET/AI/PA/CPP film and 12μm VMPET film were tested with the infrared sensor method WVTR testers before and after the improvement at 23 ℃, 90% and 38 ℃, 90%. The results showed that the relative uncertainty caused by the improved infrared sensor method tester and cup method tester was basically the same. Compared with the unimproved tester, the uncertainty of the improved infrared sensor method tester, the relative deviation of test results from the cup method, the relative deviation of each group of test data and the relative standard deviation were reduced. The reliability, accuracy, repeatability and stability of the improved infrared sensor method WVTR tester have been improved regarding the testing of water vapor trans-mission rate of packaging materials with different properties.