The utility model provides a subway underground excavation station prevents drainage structure to reduce the construction investment under the prerequisite that satisfies the tunnel water proofing requirement by a wide margin. Including arch wall subtotal base plate portion branch, the composite lining structure of arch wall part for constituting by arch wall preliminary bracing and arch wall secondary lining, base plate portion is divided into straight tunnel floor, and straight tunnel floor's below sets up base mat. Setting up arch wall drainage system between arch wall preliminary bracing, the arch wall secondary lining, setting up bottom plate drainage system between straight tunnel floor and the base mat, arch wall drainage system, bottom plate drainage system are linked together with the escape canal of tunnel both sides.