Abstract: Combined with the 2-d tidal flow mathematical model and the simulation of temperature, we analyzed the characteristics and scope of thermal discharge in different arrangements of power plant. Compared and optimized the different thermal discharge arrangements combined with the characteristics and control indices of marine sensitive areas, and given the optimal plan from the perspective of reducing the scope of influence, the influence on the marine environment and intake temperature. Results showed that the scope of thermal influence was related to topography, hydrological characteristics, arrangements and position of discharge engineering. The subsurface-distant pipe drainage was beneficial to the dilution and diffusion of thermal discharge and reduce the scope of influence. However, there were many factors affecting the diffusion range of thermal discharge and deep drainage was not always able to reduce the influence.