The invention relates to a ventilation device, in particular to a ventilation device on the top of a radome. The ventilation device on the top of the radome is used for solving the problems that an existing radome ventilation device is low in manufacturing efficiency, low in finished product quality, poor in universality of assembly with various radomes, difficult in later maintenance and poor in natural ventilation effect, rain leakage often happens, and the use performance of a radar antenna is influenced. The ventilation device on the top of the radome comprises a mushroom-shaped upper radome body, a base and turnover plates, wherein the mushroom-shaped upper radome body is buckled to the base, ventilating windows are arranged on the outer side walls of hollowed-out step platforms at the bottom of the base, and the turnover plates are installed on the ventilating windows. A connecting flange extending outwards is arranged on the edge of the mushroom-shaped upper radome body, the mushroom-shaped upper radome body is connected with the annular outer edge through the connecting flange, and a through hole is formed in the bottom surface of a hollow cylinder and provided with a connecting flange extending inwards. The ventilation device on the top of the radome is applicable to the field of wireless communication.