The invention relates to an external intervention system of vehicle rollover and an intervention method. The system comprises a rollover detection subsystem, a working area monitoring subsystem, a rollover active intervention subsystem and a system controller, wherein the rollover detection subsystem comprises a tilt angle sensor, a lateral acceleration sensor and a rollover diagnostic device, theworking area monitoring subsystem comprises visual detectors arranged on the two sides of a vehicle, the rollover active intervention subsystem comprises a plurality of actuators installed on the twosides of the vehicle; the structures of the actuators are the same, and the actuators comprise connecting shells, separation guide shells, air bag set bases, air bag sets and cutting cables. According to the system, active intervention can be performed at the initial stage of rollover, so that the vehicle is stressed by the righting moment brought by the contact between the intervention air bagsand the ground, the vehicle can returned to a stable state from an instability state, and the vehicle is prevented from occurring complete rollover.