The utility model discloses an electro-magnet safety lock for cabinet is shielded to electric power system, said electric power system screen cabinet has cabinet door and door frame, and this electro-magnet safety lock includes: preceding lock core, back lock core, electro-magnet supply circuit, the electro-magnet supply circuit include: control switch, when said electro-magnet supply circuit switches on, for the lock core power supply of said back makes said back lock core has magnetism, can the actuation lock core before said, during the control switch disconnection, the electro-magnet supply circuit open circuit. The electro-magnet safety lock is through control electro-magnet supply circuit's on-state can control whether back lock core has magnetism. When when said back lock core has magnetism, can the actuation the locking is realized to lock core before said, works as when back lock core does not have magnetism, before said the lock core with the lock core separation of said back realizes the unblock, and the easy operation of locking and unblock has improved work efficiency