The invention provides a water heater and a control method thereof. The water heater comprises a compressor, a four-way valve, a three-way valve, a first heat exchanger, a first fan assembly, a second fan assembly, a water tank, a second heat exchanger, a detection module and a controller, wherein an air outlet of the compressor is connected to the first end of the four-way valve, the second end of the four-way valve is connected to one end of the first heat exchanger, the third end of the four-way valve is connected to one end of the second heat exchanger, the other end of the first heat exchanger is connected to an outer coil pipe at the upper part of the water tank, the other end of the second heat exchanger is connected to an outer coil pipe at the lower part of the water tank, the three-way valve is arranged on a pipeline between the four-way valve and the first heat exchanger, the controller is connected to the detection module and is used for controlling start and stop of the first/second heat exchanger, the first/second fan assembly and the three-way valve according to the temperature of the outdoor environment and/or the temperature inside the water tank. The water heater and the control method thereof have the advantages that through the technical scheme, the problem that the water heater blows cold air can be effectively solved, and better customer experience can be achieved.