Abstract: To overcome the deficiency of traditional performance evaluation method for power plant condensers, a new method was proposed considering the water resistance. Based on the retrofit schemes for a certain power plant condenser, comparative analysis was conducted on the variation of water resistance before and after retrofit among various schemes, while the effects of water resistance variation were studied on the cooling water flow, circulating pump's power consumption, and then on the overall performance of the condenser, so as to find out the optimum retrofit scheme. Results show that the performance evaluation method for condensers considering water resistance is more reasonable and practicable, which therefore may serve as a reference for the decision of optimal retrofit scheme and for the follow up performance evaluation of condensers.