A water tank module and an air-conditioning water system configured with the water tank module is disclosed. The air-conditioning water system comprises an outdoor unit, a water pump, an air-conditioning terminal, a leaving water pipe and a return water pipe. The water tank module comprises: a first buffer water tank disposed on the leaving water pipe, where the first buffer water tank is integrated with a first ball valve; and a second buffer water tank disposed on the return water pipe and arranged at or near the first buffer water tank, where the second buffer water tank is integrated with a second ball valve, a safety valve for pressure relief, an exhaust valve for gas exhaust, and a water replenishment valve for water replenishment, wherein, a bypass pipe having a bypass valve is disposed between the first buffer water tank and the second buffer water tank.