Therefore, when forehead tax of water vapor transmission, the different results of test completely can be gotten under different conditions of test. That is completely different to the oxygen results and other regular gases. Therefore, the widening of scope of measurement through test gas alteration or reduction of water vapor difference is not adjusted between the two sides. 4.Conclusion With the introduction of new materials and applications, materials of high tax of transmission are to be used extensively. This article presents some staff, convenient, fast necessary half to widen scopes of measurement of instruments of barrier property. For the time being, emptying, especially emptying in the sides of packing, during test of barrier property, would have to be emphasized, to prevent errors caused for the false operation.