The futures price limit system refers to the daily maximum price fluctuation range of listed futures contracts set by the exchange, and the quotation exceeding this range will be regarded as invalid and cannot be traded.

There are two forms of price limit range: percentage and fixed quantity. For example, the daily limit of copper and aluminum in Shanghai Metal Exchange is 3%, and the absolute daily limit fluctuates with the settlement price of the previous day; The mung bean contract of Zhengzhou Commodity Exchange is based on yesterday's settlement price, and the fluctuation 1.200 yuan/ton is the price limit.

The biggest difference between futures fluctuation board and stock is that it will change with the change of market, rather than a single ratio or price.