The invention discloses a nuclear radiation excess self-locking type protective door. The nuclear radiation excess self-locking type protective door comprises a door framework and a door body hinged to the door framework, wherein one side of the door body is provided with a latch assembly; a clamping assembly is arranged in a position opposite to the latch assembly of the door framework; the latch assembly comprises a sliding groove, a mounting plate mounted in the sliding groove, an iron latch block arranged in the sliding groove in a sliding manner and a first reset spring, and the two ends of the first reset spring are separately fixedly connected with the mounting plate and the latch block; the clamping assembly comprises a latch groove oppositely arranged with the opening of the sliding groove and an electromagnet fixed in the latch groove; a coil of the electromagnet is coupled with a self-locking system; the self-locking system comprises a detecting circuit and a processing circuit; the detecting circuit comprises a nuclear radiation sensor arranged in a room, and a detecting signal is output from the signal output end of the detecting circuit; and the processing circuit is coupled to the signal output end of the detecting circuit and used for controlling the connection and disconnection of the coil of the electromagnet and the power supply according to the detection signal. The nuclear radiation excess self-locking type protective door has the advantages of being high in safety, high in reliability, convenient to use and low in failure rate.