Because the electromagnetic lock has no complicated mechanical structure and the structure of the bolt, it is suitable for the passage control of the escape door or the fire door. The inside of the lock body is protected by infusion of epoxy. At present, the suction strength of the electromagnetic lock is expressed in lb (lb), and the test method is static pressurization. The so-called static pressure is that the electromagnetic lock gradually increases the pulling force on the adsorption iron plate after the electromagnetic lock is energized. When the suction force of the electromagnetic lock is exceeded, the adsorption iron plate is pulled open instantaneously, and the data of the tension force is the tensile value of the electromagnetic lock. Moreover, the force of the electromagnetic lock and the absorbing iron plate must be face to face and a collinear load test, so that the holding force of the electromagnetic lock is the largest. The adsorbed iron plate may be temporarily magnetized due to the magnetic induction of the electromagnet for a long time.