The corrosion products in the secondary circuit of the nuclear power plant continuously accumulate and are deposited on the steam generator (SG) secondary side, which will have a great impact on the safe and economic operation of the nuclear power plant. Although the deposits thickness of a CPR1000 unit is relatively low, it has seriously reduced the heat transfer performance of the tube bundle. Based on the SG heat transfer calculation model and the matching margin of steam generator and steam turbine, a normalized SG thermal performance monitoring and evaluation model of CPR1000 unit is established. Based on the actual operation data of a CPR1000 unit, the corresponding treatment measures and suggestions are put forward. This model can predict the subsequent operation trend of SG, so as to increase the safety and economy of nuclear power plants.