In order to correctly evaluate the validity of the scheme of GTCC(Gas-Steam Combined Cycle)inlet air cooling,a method based on numerical integration is presented,which integrates the temperature characteristics of the GTCC inlet air,the of—design performance of the inlet air cooling system ,the loading rules of the machine and the local yearly standard weather data,etc.The economic evaluation to the scheme of GTCC inlet air cooling in a power plant located in South China is then carried out，with the results showing that,for every 1 ℃ inlet air temper-ature depression,the GTCC output power increases by 0.5% ,while the heat rate varies slightly.Furtherm ore,the results of the scheme of cooling the inlet air temperature from the ambient temperature(30℃)to 10 ℃show that,in the local weather conditions,an annual average temperature decrease of 16℃ of the inlet air can be obtained,as well as an annual output power increase of 8.27%and a fuel consumption rate increase of 1.03%.It is also shown that the payback period approximately amounts to 2.0 years when the peak power price is 1.00 Yuan/(kW ·h) and the fuel cost is 2200 Yuan/t.