The invention discloses a flow compensation tank type pipe network pressure-superposed water supply device. The flow compensation tank type pipe network pressure-superposed water supply device is mainly composed a flow stabilization compensation tank, a negative pressure eliminator, a flow regulating valve, a water pump and a control cabinet; the flow stabilization compensation tank comprises a dual-cavity dual-chamber horizontal type structure composed of a flow stabilization cavity, a water storage cavity, a high-pressure water chamber and a high-pressure air chamber; the negative pressure eliminator is installed at the top of the water storage cavity, and a water storage opening is formed in the bottom of the water storage cavity and is connected with a water distribution pipe through a connecting pipe; and an energy storage opening is formed in the bottom of the high-pressure water chamber and is communicated with a water supply pipe through a small flow pipe and a bypass pipe. The flow compensation tank type pipe network pressure-superposed water supply device has the beneficial effects that the dual-cavity dual-chamber horizontal type structure composed of the flow stabilization cavity, the water storage cavity, the high-pressure water chamber and the high-pressure air chamber is integrated to the flow stabilization compensation tank, the structure is compact, the occupied land is small, convenience is brought to installation and maintenance, and the water quality is sanitary; in addition, the adjusting volume for compensation of the tap water inlet amount can be increased through the water storage cavity; and the high-pressure air chamber is matched with the high-pressure water chamber for energy storage, so that small flow pump stopping, pressure maintaining and water supplying is facilitated.