The invention provides a water circulation heat-pump water heater and control method. The water circulation heat-pump water heater comprises a water tank, a plate heat exchanger and a heat-pump external machine. A circulation water outlet pipe and a first circulation water inlet pipe are arranged on the lower portion of the water tank, a second circulation water inlet pipe is arranged on the upper portion of the water tank, the circulation water outlet pipe is connected with a water inlet pipe of the plate heat exchanger, the first circulation water inlet pipe is connected with a water outlet pipe of the plate heat exchanger through a first solenoid valve, and the second circulation water inlet pipe is connected with the water outlet pipe of the plate heat exchanger through a second solenoid valve. An upper portion water temperature sensor and a middle portion water temperature sensor are arranged on the upper portion and the middle portion inside the water tank in sequence, and a circulation water temperature sensor is arranged on the water outlet pipe of the plate heat exchanger. Through the water circulation heat-pump water heater, using waiting time is shortened, energy consumption is reduced, and the utilization rate of energy resources is improved.