The invention relates to a safety distance warning device of a vehicle-mounted movable substation. The safety distance warning device mainly consists of two modules, such as four infrared transceivers and a main controller, wherein the four infrared transceivers are respectively arranged on four corners of the vehicle-mounted movable substation, and every two infrared transceivers form an infrared warning line; a transmitting part of each infrared transceiver uses an infrared light emitting diode as a transmitting element, an infrared digital pulse driving type and a single light beam shielding and sensing detection type are adopted, an infrared receiving part adopts a photo-sensitive diode to complete photovoltaic conversion, and an infrared receiving circuit of each infrared receiving part comprises an infrared sensing part, a signal processing part and a comparison output part; the main controller module comprises a wireless transmission module, a GSM (global system for mobile communications) transmission antenna, a programming interface, a power source switch, a charging interface, an indication lamp and an alarming device. The safety distance warning device has the characteristics that the detection is sensitive, the warning is timely and reliable, the structure is simple, the installation is easy, the practicality is strong, and the like.