The invention discloses a burner and a gas water heater comprising the same. The burner comprises a burner frame, a plurality of distribution parts and a gas distribution rod, wherein a premixing cavity is defined in the burner frame; the burner frame is provided with a fan connector and a gas connector which communicate with the premixing cavity; the distribution parts are arranged in the premixing cavity in the gas flowing direction at intervals; each distribution part is provided with a plurality of distribution holes communicating with the premixing cavity; the gas distribution rod is detachably arranged in the premixing cavity and defines a gas channel; the gas distribution rod is provided with a gas inlet and gas outlets, the gas inlet communicates with the gas channel, and the gas outlets communicate with the premixing cavity. The burner provided by the embodiment of the invention is simple in structure; gas is supplied relatively uniformly; a mixture of gas going into all areas of the burner and air is distributed uniformly; the machining and manufacturing cost is low; fuel waste is reduced; emissions of pollutants such as nitrogen oxide and harmful substances such as carbon monoxide, hydrocarbon and tar are reduced; and the space in the premixing cavity is saved.