In the two step  process of production of melamine, as the hot air filter unit temperature was high, there were some by-products in the crude melamine which purity was low, the crude melamine should be heated and dissolved again using of steam in the refining process,then cooled and crystallized in the crystallization tower ,finally, the high purity melamine product was obtained.In this process, a large amount of steam was consumed, the production cost was increased. A new process was proposed in the two step process. The hot air cooling unit was added for the first time.The temperature of the hot air was reduced, and the by-product steam was isolated from the high boiling point reaction by-products, the air was purified, at the same time, the high purity crude product of melamine was got. Because of the change of the refining process, the consumption of steam was greatly reduced, the production cost was saved, the market competitiveness of products was improved.