Molecular sieve is a kind of crystallized aluminosilicate .Owing to its even pore diameter and high specific surface areas, it has many excellent features: 1、 selective adsorption ,that is to say it will absorb the moleculars of which the diameter is less than the pore size of molecular sieve. 2、 As for polar moleculars and unsaturated molecular, it has selective adsorption.The bigger the polarity .the higher unsaturated ratio,the stronger selective adsorption. 3、 Strong property of water absorption even in high temperature,large space velocity or low content of water, it has quite a higher water absorption capacity. XINTAO molecular sieve has divided into several types of 3A, 4A, 5A, 13X, IG Desiccant, 13XAPG, Refrigerant Desiccant according to its use.