The order quantity should match the revenue quantity. Find potential suppliers or buyers for enterprises with purchase and sale needs, and enterprises with matching supply and demand will voluntarily realize effective purchase and sale according to the principle of marketization. The basis of order matching principle is that the order quantity should match the revenue quantity. The purchase and sale contract mainly refers to the agreement that the supplier and the buyer deliver the products to the buyer according to the consensus, and the buyer accepts the products and pays the price according to the regulations.