The invention discloses a condensing efficient gas water heater, which comprises an inner container, a combustor, a smoke exhausting hood, a heat exchange smoke tube, a heat-preserving layer and a shell, wherein the combustor is arranged at the lower side of the inner container; the smoke exhausting hood is arranged at the outer side of the inner container and has a smoke exhausting gap with the inner container; the heat exchange smoke tube longitudinally runs through the inner container; the heat-preserving layer and the shell are coated at the outer side of the smoke exhausting hood; the smoke exhausting hood is provided with a smoke exhausting opening communicated with atmosphere; the smoke exhausting hood particularly comprises a gas distributing hood at a top, a condensing hood positioned at the lower side of the gas distributing hood and further connected with the gas distributing hood, and a reflux hood arranged at the lower part of the heat-preserving layer; a reflux cavity is formed between the reflux hood and the condensing hood; the reflux cavity is respectively communicated with the smoke exhausting opening and a condensing cavity; and the outer wall of the condensing hood is provided with a first heat insulating layer. According to the condensing efficient gas water heater, by arranging the first heat insulating layer on the outer wall of the condensing hood, the first heat insulating layer can be used for reflecting the heat of fume, so that the heat of the fume is not leaked outwards; the first heat insulating layer is verified to be capable of decreasing the temperature at the smoke exhausting opening by 2-5 DEG C; and the heat efficiency is further improved.