Abstract: In view of the direct air-cooled power generating unit under the action of the environment wind, fan cooling capacity of the air-cooled condenser（ACC） would vary differently in different areas, when influenced by the exhaust recirculation and the coupling effects of axial fan cluster pumping. This variation would lead to higher power consumption and lower energy efficiency for the traditional back-pressure control strategy. Through the use of the computational fluid dynamics（CFD） method, the air flow field and temperature field of the axial flow fan cluster array could be obtained, and the back pressure of the unit in the different fan speed would be calculated, then the grey differential incremental correlation method was proposed to analyze the influence on the back pressure of the unit when processed the speed regulation of air-cooled island wind turbine generators, and then took the working efficiency of single air cooling cell into consideration when researched the pressure regulation problem. The results show that, larger the fan ventilation rate will not necessarily cause higher the heat transfer efficiency of the finned tube bundle of the air-cooled unit. Rational usage of efficient air-cooled unit can effectively improve the energy efficiency of air cooling island, and achieve the purpose of energy saving. It will also be able to provide theoretical andexperimental basis for further research on the control of axial flow fan in air-cooled island.