The present invention provides an autonomous emergency braking system of a vehicle including a sensor module which radiates a signal when the vehicle is being driven to the front of the vehicle to detect an object in front of the vehicle, an autonomous control module which determines whether the object collides with the vehicle and when it is determined that the object collides with the vehicle, puts the brake on the vehicle, and a sensor control module that when the vehicle puts on the brakes and is forwardly inclined, adjusts a signal radiating direction of the sensor module to control the sensor module to detect the object.