A vehicle body reinforcing structure for coping with a small overlap collision may include front side members which may be extended in a longitudinal direction of a vehicle and disposed at left and right sides in a width direction of the vehicle, a crash box which is installed to a front end of the front side member in the longitudinal direction of the vehicle and absorbs and reduces impact when receiving the impact to be deformed, a bumper beam which is disposed in front of the crash box in the longitudinal direction of the vehicle, coupled to the crash box, and extended in the width direction of the vehicle, and a reinforcing member which is coupled to both the crash box and the front side member, and protrudes outside of the bumper beam in the width direction of the vehicle to transfer an impact energy to the front side member.