A rear body structure of a vehicle includes a wheel housing inner panel, and a common mounting bracket which is engaged with an outer surface of the wheel housing inner panel in a forward/backward direction of the car body and has insertion holes formed therein such that a two-wheel shock absorber and a four-wheel shock absorber are inserted into the holes, respectively, and an inner quarter connecting member which connects the common mounting bracket to an inner quarter panel to reinforce a rigidity of the bracket. Accordingly, a single common mounting bracket can be applied to a two-wheel drive system and a four-wheel drive system, without the need of separately manufacturing and assembling a bracket for a two-wheel shock absorber and a bracket for a four-wheel shock absorber, and thus the manufacturing cost of the rear body structure can be reduced. Also, since the common mounting bracket, which is commonly applied to the two-wheel drive system and the four-wheel drive system, is fixed to the wheel housing inner panel, in formation of the structure for improving the rigidity of the car body through connection of the common mounting bracket to the inner quarter panel, it is not required to differentiate depending on whether the system is the two-wheel drive system or the four-wheel drive system. Thus, it is possible to provide a very effective structure for improving the rigidity of the car body.