Abstract: Under the background of carbon neutralization and carbon peaking, the heat exchange of vacuum system becomes one of the main factors affecting the coal consumption of the unit. Optimisation of cold end system of the unit is the best way to save energy and improve the economy of the power plant, and the level of cooling tower heat dissipation performance plays a crucial role. In this paper, numerical simulation is used to study the impact of unequal height layered arrangement renovation on the cooling tower The results show that when the filling thickness of 1m increased to 1m-1.25m-1.5m layered distribution, the tower recirculation zone is smaller, the velocity distribution is more uniform. The humid air temperature rises, and the heat transfer is significantly improved, which can effectively reduce the temperature of the condensed water. The unequal height layered arrangement improves the thermal as well as resistance characteristics of the tower, and the modification of layered arrangement of packing can reduce the back pressure of the turbine and improve the operating efficiency of the power plant.