Trend trading indicators. DMI trading index, also known as trend trading index or trend trading index, is a technical analysis method of medium and long-term financial futures market. The basic principle of DMI trading index is to find the function of the price hitting a new high or a new low in the process of ups and downs, judge the long and short power, and then find the equilibrium point of buyers and sellers and the cyclical process of their fluctuation under the interaction of both parties.