The invention discloses a portable electromagnetic radiation warning device, which comprises a fixed plate, a connecting plate and a detector, the bottom surface of the fixing plate is welded and connected with the top surface of the connecting plate, the top surface of the detector is embedded and connected with the bottom surface of the connecting plate, and the detector includes The back cover, the heat dissipation block, the alarm, the irradiation board, and the input block, the heat dissipation block is embedded in the left side of the back cover, the alarm is embedded in the bottom surface of the back cover, the top surface of the irradiation board is embedded and connected with the inner layer of the back cover, and the present invention uses electromagnetic radiation It enters the detector and is received by the irradiating panel to monitor the amount of external electromagnetic radiation, and promptly warns through the alarm when the radiation amount is too high. The internal pressure of the outer plug quickly pushes outward, and then knocks down the accumulated snow layer on the outer layer, so as to avoid the problem that the radiation is reflected by a large amount and it is difficult to enter due to the accumulation of snow layer, which will cause the problem of decreased monitoring accuracy.