Abstract: Overnight risk prevention and monitoring is the focus of attention of investors and regulatory authorities. It is of practical significance to explore effective ways to reduce overnight risk.Based on information and investor behavior, this paper constructs a theoretical model of overnight risk of commodity futures affected by night trading. According to the changes of volume and speculation of various commodities before and after the implementation of night trading and the correlation between different commodities, 10 representative varieties of metal, agricultural products, black series and chemical commodities futures are selected to test the research hypothesis empirically.The results show that night trading can reduce the overnight risk of commodity futures. Moderate speculation in the futures market is the cornerstone of the system, but there is no time effect on the overnight risk of commodity futures. Regulatory measures should be taken to avoid overspeculative futures trading.

Key words: night trading, commodity futures, the overnight risk；time effect