Designed by the principle of weighting method use weight reduction method (dry cup method) to test the moisture transmittance rate of plastic films, applicable to all kinds of plastic packing, food, medicine, cosmetic manufacturer and quality inspection institutions of higher schools and quality inspection. Accord with international standard of GB/T join, GB, ASTM E96, ASTM 16928 D1653, TAPPI T464, ISO 2528.Computer automatic test and automatic controlling temperature, humidity, automatic recording temperature, humidity, weight, transmission rate which four groups curves, automatic judging experiment ending.