The variation of the internal temperature field and airflow field in the evaporative condenser was discussed when it was worked under an unsteady state numerical simulation by using CFD software. The performance of internal temperature field and airflow field was analyzed when the condenser worked within 5 s with different air inlet direction (single inlet, double inlets, and three inlets). The simulation results showed that when the condenser worked with single inlet, the cold airflow was easily infiltrated the bottom of the condenser horizontally, then rose and got heat exchange with coils under the effect of density difference. The condenser which has double inlets could decrease swirls’ number and intensity that caused by the disturbance of coils and walls. Furthermore, when the condenser worked with three inlets, the cavity temperature of condenser would experience a process of fall first and then rise. In the future study, the airflow inlet area and air inlet angle can also be changed to optimize the heat transfer efficiency of the evaporative condenser.