The invention discloses a domestic hot water supply system which comprises a gas water heater, a near end faucet, a far end faucet, a first temperature detector, a water storage box and a controller. An auxiliary water way is provided with an electromagnetic valve. The water storage box is connected to a water inlet pipe of the far end faucet through a water supplementing way. The water supplementing way is provided with a water pump. Under the condition that the far end faucet is opened and the gas water heater automatically works, if the first temperature detector detects that the temperature of water flowing out of the far end faucet is lower than a first temperature set value, a liquid level sensor detects that the liquid level in the water storage box is higher than a liquid level set value, and a second temperature detector detects that the water temperature in the water storage box is higher than a second temperature set value, the controller controls the water pump to be started and work for a period of time, and therefore water in the water storage box is pumped to the far end faucet and flows out of the far end faucet. The situation that completely-unheated cold water flows out when the far end faucet is opened is avoided, and using comfort is improved.