The utility model discloses an active ventilation cooling system of a radar radome, and relates to the field of active ventilation cooling of radar radomes. In order to solve the problems that the ventilation cooling capacity is greatly influenced by wind power and wind direction in the nature and the heat dissipation requirement of a high-power radar antenna cannot be met due to the fact that a ventilation opening is formed in the top of an antenna cover of an existing radar antenna ventilation device. The radome is in the shape of an open hemisphere with a cavity. A top ventilation opening is formed in the top end of the radome; a plurality of active ventilation cooling devices are arranged at the bottom end of the radome along the circumferential outer wall; the air outlet ends of the active ventilation cooling devices penetrate through the outer wall of the radome, the multiple active ventilation cooling devices are symmetrically arranged in pairs with the center of the bottom endof the radome as the center, and a draught fan controller is arranged on the bottom face of the interior of the radome and used for controlling starting and stopping of the active ventilation coolingdevices. The cooling device is suitable for cooling the radar antenna during working.