Abstract: Based on CFD code FLUENT,three-dimensional numerical analyses were carried out for natural draft wet cooling tower under crosswind conditions.Sensitivity analyses to parameters such as ambi-ent crosswind velocity profile and water droplet equivalent diameter validated the adopted numerical model.The effect of crosswind on wet cooling tower inner and outer aerodynamic field and tower internal heat and mass transfer performance were investigated numerically.The results show that crosswind causes the in-crease of air inflow relative departure degree and induces horizontal air mass flow rate which improves rain zone heat and mass transfer but reduces tower vertical air mass flow rate,and then produces an unfavorable effect on fill zone and increases outflow water temperature.The analyses about air inflow relative departure degree show that improving the air inflow aerodynamic field can reduce the unfavorable effect of crosswind on the circumference distribution of air inlet air radial velocity and then improve the total cooling perform-ance of wet cooling tower under crosswind conditons.