The invention discloses a gas water heater having a freezing prevention function, and relates to a water heater. The gas water heater having the freezing prevention function comprises a housing, wherein a fuel gas pipe is fixedly connected with the lower right portion of the housing, the flue gas pipe penetrates through the housing and is connected with a combustor, a sensible heat exchanger is fixedly connected with the upper portion of the combustor, a condensation heat exchanger is fixedly connected with the upper left portion of the interior of the housing, a water inlet pipe is fixedly connected with the lower left portion of the housing, the water inlet pipe in S shape penetrates through the condensation heat exchanger and the sensible heat exchanger, and then penetrates through thehousing, and locates on the outer side of the housing, and a draught fan is fixedly connected with the upper right portion of the interior of the housing. The gas water heater having the freezing prevention function is simple in structure and convenient to use, can effectively prevent an internal water pipe from freezing in use, and thereby avoids a cracking situation of the water pipe, improves applicability under cold environment, guarantees that internal water cannot freeze through an electrical heated tube, and additionally can collect the water from a water collection tank, avoids a waterwaste circumstance, and is good in use experience and reasonable in structure design.