Abstract: The effects of heat produced by radiators were ignored in existing research of internal suctions of large cooling towers. The world's tallest reinforced concrete cooling tower with a height of 220 m which is being built in China was taken as the research object. Based on the computational fluid dynamics method, the internal flow field of the tower was simulated under wind-thermal coupling. On the basis of the numerical simulation, three-dimensional effects of the inner surface wind load for super large cooling towers were analyzed, and the circumferential and meridian distribution laws of the internal pressure were summarized. The difference of flow field characteristics, pressure coefficients, drag coefficients and wind resistance after considering the temperature field was also analyzed. Finally, values of the internal pressure coefficients for super large towers were recommended. The results show that the internal pressure coefficient is increased after considering the action of wind-thermal coupling, meanwhile the drag coefficient and pressure differential between the inlet and outlet are increased. It is advised to take the internal pressure coefficient as -0.43 for such super large cooling towers under true wind-thermal coupling conditions.