The invention provides an instant-heating and instant-cooling water supply system. The system comprises a water tank, a water tank pipeline, a cold storage mechanism, a heat storage mechanism, a wateroutlet pipeline and a pumping device. The cold storage mechanism comprises a phase change cold storage body, a refrigeration module used for refrigerating the phase change cold storage body, and a first pipeline, wherein the phase change cold storage body is in contact with the first pipeline, and the first pipeline is connected between the water tank pipeline and the water outlet pipeline. The heat storage mechanism comprises a phase change heat storage body, a heating module used for heating the phase change heat storage body, and a second pipeline, wherein the phase change heat storage body is in contact with the second pipeline, and the second pipeline is connected between the water tank pipeline and the water outlet pipeline. The pumping device is arranged on the water tank pipelineor on the water outlet pipeline. In addition, the invention also provides a water drinking device with the instant-heating and instant-cooling water supply system. Heat storage and cold storage can beeffectively carried out, hot water and cold water are provided immediately, repeated refrigeration or heating is avoided, and energy conservation and environmental protection are achieved.