The work aims to study the application of desiccant method and water method based on the principle of gravimetric method in the field of different packaging materials. The compared deviation caused by the test error induced by the manpower, environment and other factors was avoided. An intelligent detection instrument which comprised automatic weighing in the water vapor permeability test chamber was adopted. According to desiccant method and water method of ASTM E96, the water vapor transmission rate of seven kinds of different materials and moisture retardant samples at different experimental temperatures and humidity, including plastic film, paper-aluminum-plastic composite film, artificial leather and non-woven fabric were tested and compared. For samples of paper-aluminum-plastic composite film, artificial leather and non-woven fabric, there was significant deviation of results measured respectively in desiccant method and water method, but no obvious difference for other four samples. For artificial leather sample, the test result of desiccant method was obviously greater than that of water method, but the result was opposite for paper-aluminum-plastic composite film and non-woven fabric. The desiccant method and water method cannot be applied to all packaging materials in any condition for the testing of water vapor transmission rate. The desiccant method or water method should be selected reasonably based on some factors, such as the sample material, structure, operation conditions and actual application.