Abstract: In this paper, we calculated the radioactive Concentration distribution of radioactive waste water, the temperature distribution of cooling water which drained and the effect of impingement from the Dayawan Nuclear Power Station on nearby waters range, discussed and analysed some problems of Computational results and computatin with Alternating Direction Implicit Method (ADI). The contents of the article indued: the establish of two-dimension tidal current equation, radioactive waste water pollutant dispersion equation and cooling water heat convection diffusion equation, the numerical difference calculation model of tidal current field, concentration field as well as temperature field, effect impingement with ADI method, numerical calcuation results.The result of research showed that: when the Dayawan Nuclear Power Station is on normal operation and after the low Level radioactive waste water and Low temperature cooling water have been drainde off into the sea, it is found that the radioactive concentration is near and enen Lower than the natural background radiation just outsite the area of about 4km² round the water outlet, the temperature difference is not obrious just outside the area of about 6 km² round the water outlet, the effect of impingement of abont 4.3%.