First of all, you should understand the principle of spot arbitrage of stock index futures: spot arbitrage is an arbitrage transaction that uses the pricing deviation between stock index futures contracts and their corresponding spot indexes. That is, when the price difference between the futures and the spot deviates to a certain extent, you can buy (sell) the stock index futures contract and sell (buy) the underlying index spot stock portfolio with the same value, and close the position at the same time in the future. The common decision-making method of spot arbitrage of stock index futures is to compare the actual price and theoretical price of stock index futures to judge whether there is arbitrage opportunity and what kind of arbitrage transaction to conduct.