The invention discloses a purified drinking water pipe network pressure-superposed secondary water supply system. The purified drinking water pipe network pressure-superposed secondary water supply system is mainly composed of a flow stabilization tank, a non-negative-pressure controller, a pressure pump set, a membrane purification water processing device, an intelligent control cabinet and a water using point. The flow stabilization tank and the non-negative-pressure controller are installed in a matched mode, and the non-negative-pressure controller is installed on the flow stabilization tank to be used for eliminating pipe network negative pressure; outlet water of the flow stabilization tank is connected with the pressure pump set, and a water distribution pipe is connected to the membrane purification water processing device through outlet water of the pressure pump set; a membrane pressure detecting meter, a membrane self backflushing control device and a water quality on-line monitoring device are arranged on the membrane purification water processing device; and a water supply pipe is connected to the water using point through outlet water of the membrane purification water processing device for water supply. The purified drinking water pipe network pressure-superposed secondary water supply system has the beneficial effects that the membrane purification water processing device is integrated to the r pipe network pressure-superposed secondary water supply system, so that the advantages of energy saving and land saving of pipe network pressure-superposed secondary water supply are achieved; in addition, the functions of water quality improving and guaranteeing are increased, so that the water quality of the water using point, and the obvious social economy effect is achieved.