Taking the cold end system with dual-pressure condenser of 1 000 MW coal-fired unit of Huainan Pingwei No.3 Power Generation Co., Ltd. as the research object, considering real-time parameters during operation, the full working conditions real-time optimization model was established. Based on the historical operation data, the accuracy of the model was verified, the influence of changes in real-time state parameters such as load, circulating water inlet temperature and clean coefficient on the optimization calculation results was analyzed, and the optimal circulating pump operation mode and energy saving potential under calculated working conditions were obtained. The calculation results showed that, 63.44% of the calculation conditions had achieved energy saving effect, and the cumulative income could reach 604.16 MW·h, it is more necessary to reasonably determine the optimal operation modes of the circulating water pump under the working conditions of high load and high inlet water temperature.