Futures trading should implement the margin system. When buying and selling futures contracts, traders can pay a certain percentage of the contract value (generally 5%- 15%) as performance guarantee, so they can trade several times as much as the deposit. This kind of margin trading is also called "leveraged trading". This feature of futures trading makes futures trading have the characteristics of high returns and high risks. The lower the margin ratio, the greater the leverage effect, and the more obvious the characteristics of high returns and high risks. The higher the margin ratio, the smaller the leverage effect.