The invention relates to a geomembrane seepage-proofing gravel stone dam which comprises a dam base, a dam body composed of gravel and a back-pressure platform connected with a water draining edge body. The dam body and the back-pressure platform are located on the dam base. The back-pressure platform is connected with the dam body. The dam body comprises an upstream dam body and a downstream dam body, the part, provided with the downstream dam body, of the dam base is provided with multiple vibration flotation gravel piles with the depth of 15 m, wherein the multiple vibration flotation gravel piles are distributed in a regular triangle shape, and the distance between every two adjacent vibration flotation gravel piles is 4 m. The dam face of the upstream dam body is provided with a composite geomembrane which is used for seepage prevention. By means of the geomembrane seepage-proofing gravel stone dam, the vibration flotation gravel piles and the dam base form a composite foundation, the back pressure platform is matched, and the problem of liquidation of the foundation is effectively solved; an L-shaped draining body arranged in the dam body is connected with the downstream water draining edge body, the upstream part of the vertical water draining body is provided with an inverse filtering protection layer, and a very good prevention effect is achieved on losing of fine particles in gravel materials of the dam body and the dam base; and the geomembrane is adopted on the upstream dam face of the composite gravel dam for seepage prevention, and the seepage prevention effect of the geomembrane seepage-proofing gravel stone dam is particularly obvious.