A shock absorber mounting portion structure of a vehicle may include a quarter panel, a wheel housing inner panel coupled to the top of the quarter panel to form a wheel house, an inner support member coupled to an upper surface of the wheel housing inner panel and a portion of the quarter panel to form a closed space together with the wheel housing inner panel and the quarter panel, wherein the portion of the quarter panel may be disposed above the top of the quarter panel, an outer support member coupled to the quarter panel to form a closed space together with the quarter panel to correspond to the inner support member around the quarter panel, and a mounting bracket of which the top may be coupled to the wheel housing inner panel through a horizontal bonding surface so as to support the top of a shock absorber.