The introduction of stock index futures will not cause market shocks. On the contrary, the trend of the stock index will tend to be flat. With the introduction of stock index futures, the bilateral market structure will be improved and hedging transactions will become a reality, which will profoundly change the A-share market transactions. After the introduction of stock index futures, the linkage among futures market, spot market and money market will make the market changes more complicated; Hedging transaction will make investors' operation more flexible and control risks more abundant, and the hedging function of futures market will help reduce the risks in spot market. Specifically, the introduction of stock index futures will affect the A-share market in the following aspects: the trend of stock index will tend to be flat. From the development history of mature markets, it can be seen that the fluctuation range of stock index of unilateral trading in spot market is much larger than that of futures and spot bilateral trading markets with hedging trading mechanism. Excluding the impact of major events on the stock market, the violent fluctuations of stock indexes mostly occur when the market trend is uncertain. In a unilateral market, investors are either long, short or not. In addition to not doing it, the other two options will face huge risks, which will encourage the fluctuation of the stock index. In the bilateral market, if the stock index fluctuates greatly, investors can make opposite hedging transactions in the futures market, no matter whether they choose to be long or short, so as to obtain average returns and resolve risks. Whether it is a big rise or a big fall, stock index futures can get huge hedging income, and a large amount of funds will enter the futures market. Under the action of the futures market, the spot market price will gradually level off and the stock index will converge, thus reducing the fluctuation range of the stock index. The principle of using stock index futures to hedge is to do opposite operations in the spot currency field and futures currency field of stock index according to the same trend of stock index and stock price changes to offset the risk of stock price changes. The price of a stock index futures contract is equal to the number of points in the stock index multiplied by the specified price at each point. The price of various stock index futures contracts is different at each point. For example, the price of the Hang Seng Index is HK$ 50 per point, that is, every time the Hang Seng Index drops a little, the buyer (bull) of the futures contract will lose HK$ 50 per contract and the seller will gain HK$ 50 per contract. For example, an investor holds 10 listed stocks with a total market value of HK$ 2 million in the Hong Kong stock market. The investor predicted that the financial crisis in Southeast Asia may trigger an overall decline in the Hong Kong stock market. In order to avoid risks, he hedged and sold the Hang Seng Index futures with a three-month maturity at the price of 13000 points. In the next two months, the stock market really plummeted. The market value of the shares held by investors has depreciated from HK$ 2 million to HK$ 6,543,800 +0.55 million, and the stock spot market has lost HK$ 450,000. At this time, Hang Seng Index futures also fell to HK$ 654.38+00,000, so investors closed their positions in the futures market and bought the original three contracts, achieving a profit of HK$ 450,000 [(654.38+00]] Similarly, stock index futures, like other futures, can make use of the bid-ask difference to speculate. The investment value of large-cap blue-chip stocks is highlighted in the bilateral market, and the heavyweights can represent the trend of the stock index. Heavyweights are necessary tools for stock index hedging transactions. Therefore, investors who intend to hedge must hold enough heavyweight chips in the spot market, thus driving the share price of large-cap blue-chip stocks to rise. Before the stock index futures investors complete their positions, the rise of blue-chip stocks in the market is inevitable. Some scholars engaged in stock index futures research pointed out that the valuation of large-cap blue-chip stocks will rise from 20%-30% below their actual value to 20%-30% above their actual value, and HSBC's share price has been hovering above 100 Hong Kong dollars for a long time. The investor structure will undergo profound changes. The investment of stock index futures is professional and risky, and its investment concept and risk control are essentially different from those of stock spot market. In the competition with institutional investors, small and medium-sized investors often lack the necessary investment skills and have low ability to resist risks, so the risks they face are far greater than those of institutional investors. On the other hand, the investment threshold of stock index futures is high, requiring investors to invest more than 400,000 yuan. The latest statistics show that among the total investors in the A-share market, 89% have funds of 300,000 yuan or less, and 95% have funds of 500,000 yuan or less. Therefore, after the introduction of stock index futures, it will be mainly institutional investors who can hedge, and it is difficult for small and medium-sized investors to directly benefit from the stock index futures market. Mature market data show that the annual returns of international hedge funds are mostly between 10%-30%, which is also a good return for small and medium investors. Therefore, it will be a wise choice for small and medium investors to choose investment funds and indirectly benefit from the stock index futures market. It can be predicted that the market structure with institutional investors as the main force will be more obvious. It will be more difficult to manipulate the market and fundamentally suppress it. First of all, under the bilateral market structure, the dual role of futures and spot markets can be suppressed, and the violent fluctuation of the broader market can be suppressed. In a flat market, it will be very difficult to raise or suppress a stock significantly, which makes trading impossible. Secondly, farming is the product of specific historical conditions. In the unilateral market, there is a single variety of transactions, either low-risk and low-yield bond products or high-risk and high-yield stock products. There is no other choice. Stock trading has become the means to get the most benefits, but the price of stock trading is also tragic. In the history of China stock market for more than ten years, it is not uncommon for all-powerful securities companies to collapse, and many of them have fallen on farms. If the risk of investment products provided by the market is relatively small and the income can reach 10%-30%, I believe rational investors will give up doing business.