Centralized delivery: that is, after the last trading day of the delivery month, all expired contracts are delivered at one time. Decentralized delivery: that is, in addition to all mature contracts delivered in pairs after the last trading day of the delivery month, delivery can also be made at a specified time between the first trading day and the last trading day of the delivery month.

As a financial derivative, futures are mainly used to hedge the risks brought by the spot market. Futures is a standardized contract developed from forward contract, which is a contract with others to buy forward goods, so as to achieve the purpose of hedging.