The BWS-WX box type non negative pressure water supply system greatly improves the storage capacity compared to tank type non negative pressure water supply equipment, expands the application range of water supply equipment, and avoids many disadvantages caused by the large volume of the water tank. The booster pump unit of this device can directly draw water from the municipal pipeline network or from the water tank. When there is sufficient water supply from the municipal pipeline network, the booster pump group stacks and pressurizes the water supply based on the pressure of the municipal water supply pipe; When the municipal water supply network is insufficient, the boosting device automatically starts with variable frequency according to the pressure of the municipal water supply network. The zero pressure water stored in the water tank is pressurized by the boosting device to the pressure of the municipal water supply network and then enters the booster pump group, thus achieving dual inlet water. This equipment not only retains the energy-saving characteristics of tank type non negative pressure water supply stacking, but also increases the regulating and storage capacity of the equipment's water supply, ensuring the safety of water supply.