The present disclosure relates to an active rear collision avoidance apparatus and method. The apparatus includes a sensor for acquiring information by detecting at least one of a preceding vehicle, a vehicle at risk of collision or other vehicles; and a controller for determining a possibility of collision between the vehicle at risk of collision and the host vehicle, determining a direction of avoidance preferentially from where an avoidable area exists in response to the driving of the vehicle at risk of collision, if the possibility of collision is higher than or equal to a threshold point, controlling the host vehicle to drive to avoid in the determined direction of avoidance, and controlling the host vehicle to drive to avoid a possible collision in response to a response to the transmitted avoidance request signal from the preceding vehicle and/or the other vehicle.