Abstract: Concerning the problems of low-flow, high-head and high-energy-consumption that existing in the operation of closed circulating cooling water pump in winter, the scheme of two-speed motor has been selected from a variety of feasible solutions, which is the most cost efficient and best solution for operation. The feasibility, technical and economic efficiency of the scheme have been analyzed and demonstrated. The results show that the scheme has the advantage of reducing the energy consumption, and has remarkable energy-saving effect. Guangxi Qinzhou 2 GW power plant is the first one implementing this scheme in domestic. Compared to the conventional scheme, these two units can save 1.231 2 GWh each year, and generate the total amount of revenue of RMB4,085,300 during the full life circle. This scheme can be widely used in the design of the cooling water system for auxiliary machines in various types of power plant.