Generally speaking, when the futures contract expires, the futures price should be the same as the spot price, otherwise there will be risk-free arbitrage opportunities. Before the expiration date of futures contracts, futures and spot are not only affected by the relationship between supply and demand, but also by the holding cost. The factors affecting futures prices are basically the same as those affecting spot market prices. Therefore, futures prices and spot prices will show a positive correlation trend most of the time. In the futures market with the same trading volume as the spot market, whether the futures price is ahead of the spot price or the spot price is ahead of the futures price, the sample research results of different commodities, different countries and different periods are inconsistent. Due to the different market structure and legal restrictions of various commodities, the function and adequacy of the futures market to reflect the changes in spot supply and demand are also different. But generally speaking, the futures market is more responsive to information. Because the spot market needs huge funds, even if it involves real factors such as ownership and control, the long and short power is limited and it is impossible to get a complete response. These limited forces can be fully exerted in the futures market, so the futures market has the function of price discovery.