There are two aspects of contract liquidity, one is the liquidity of the main contract in the current month, and the other is the liquidity of various varieties. Generally speaking, the main contract has good liquidity and active trading, and the contract near the delivery month has poor liquidity and large bid-ask spread; The fluidity of each variety is different. The sugar in Zhengzhou Commodity Exchange is mainly made by Wanda's customers. The price of the handling fee refunded by the exchange to their company is not easy to grasp. PTA is also good, and the trend is strong. Others, such as wheat and cotton, are basically dead. The liquidity of Dashang and Shanghai Stock Exchange (excluding gold) is relatively good.