Investors can trade 100% forward contracts with a margin of about 5%, and trade large forward contracts with a small amount of funds. Through this "leverage effect", funds can play a greater role, reduce the burden of hedgers and promote the hedging function. It also shows the high credit characteristics of futures trading. The margin system can ensure that every transaction and position it holds has the capital guarantee suitable for the risks it faces, so as to deal with the persistent gains and losses in the transaction in time and eliminate the debt phenomenon. The strict implementation of the futures trading margin system provides a safe and reliable guarantee for the performance of futures contracts. Margin system is the core of risk management in futures market, and its level is closely related to the safety and efficiency of futures market. When the margin is too low, the risk ability of the futures market to resist price fluctuations decreases, and the risk of default by investors increases. For example, overdraft, including passive overdraft and short position, is more likely to occur in the futures market, which is not conducive to the safe operation of the futures market. When the margin is too high, the number of contracts bought with the same funds will decrease, the trading volume and positions in the market will decrease, the activity may be affected, and even a certain variety will withdraw from the market.