At present, the settlement price of domestic stock index futures is calculated according to the arithmetic average price of the last two hours of the index delivery date of the spot target. In order to ensure the normal delivery of stock index futures, the index fuse will not be implemented after the market opens at 13:00 pm on the delivery date of stock index futures. Specifically, there are two situations: First, the index fuse will not be implemented from 13:00 to 15:00. For example, the Shanghai and Shenzhen 300 Index rose by more than 5% for the first time on the stock index futures delivery date 13:32, and no fuse was implemented; Second, the index implemented in the morning blew out and resumed trading at 13:00 at the latest. For example, on the delivery date of stock index futures, 5% fuse is triggered at 1 1:20 in the morning, and trading resumes at 13:00 in the afternoon (if it is a non-stock index futures delivery date, trading resumes at 13:05 in the afternoon).