Abstract: The Qing government implemented the policy of the strictly monopolized the operation of Yunnan copper mines, buying the copper for several times lower than the free-market price and wholesaling at relatively higher prices to coinage agencies. By earning the price differences of the centralized buying and selling, the government got a great deal of monopoly profit—the so-called “Copper Interest.”  By using the cheaper copper obtained at below-market prices, the coinage agencies reduced the coinage cost vastly and secured rich rewards—the so-called “Coinage Interest.” Furthermore, coinage agencies maximized the“Coinage Interest”through approaches such as selling coins or offering military pay, and taking advantage of the high market price of copper coins. “Copper Interest”was direct profit to the Qing government that resulted from the monopolized operation of Yunnan copper mines. “Coinage Interest”was the indirect profit of the copper monopoly, which was the transfer of profit from copper monopoly to coinage．