The utility model discloses a water inlet structure of a coffee machine. The coffee machine is provided with a brewing unit. The water inlet structure of the coffee machine comprises a water tank, a heating device and a pump, wherein a temperature sensor is arranged on the water tank and the water tank is connected with a water injection pipeline; the heating device is provided with heating pipes communicated with the water tank; the pump is connected with the water injection pipeline, and the water injection pipeline is connected with the brewing unit of the coffee machine. The water inlet structure of the coffee machine has the benefits that as the heating device of the water inlet structure of the coffee machine is provided with the heating pipes communicated with the water tank, and the two end parts of the heating pipes are respectively arranged in the water tank, so that water in the water tank can be introduced into one end part of the heating pipe and led out from the other end of the heating pipe to the water tank after being heated by the heating pipes, so that the cold water in the water tank is circularly heated, therefore, the size of the coffee machine and the space occupied by the coffee machine can be reduced without additionally arranging a heating tank; the water inlet structure of the coffee machine only needs to use one pump, so that the component cost can be reduced.