The invention discloses a pipe network pressure-superposed self-contained well secondary water supply system which mainly consists of a tap water pipe network, a backflow preventer, a self-contained well, a well pump, a well water pipe, a negative pressure eliminator, a flow stabilization tank, a water sterilizer, a control cabinet, a water pump, an air pressure water tank and a water using point. The tap water pipe network is connected with the well water pipe of the self-contained well and then is connected with an inlet of the flow stabilization tank, the well pump and a liquid level signal device are installed in the self-contained well, a check valve is installed on the well water pipe for water outputting of the well pump, a remote transmitting pressure gauge and the negative pressure eliminator are installed on the flow stabilization tank, an outlet of the flow stabilization tank is connected with the water pump through a water suction pipe, the water sterilizer is installed on the water suction pipe, an outlet of the water pump is connected with a water supply pipe, and the remote transmitting pressure gauge and the air pressure water tank are installed on the water supply pipe and connected with a water using point through the water supply pipe. The pipe network pressure-superposed self-contained well secondary water supply system has the advantages of adopting the tap water pipe network and the well water pipe to achieve united water supply and mutual standby application, being capable of achieving an automatic switching function and being high in automation degree, capable of saving energy, convenient to use and the like.