The invention discloses a catalytic combustor and a gas water heater with the same. The catalytic combustor comprises a combustor frame and a catalytic converter. A premixing cavity is arranged in the combustor frame in a defined manner, and a gas inlet and a gas outlet which are communicated with the premixing cavity are formed in the combustor frame; the catalytic converter is arranged on the combustor frame, is positioned at the gas outlet and is structured in such a manner that gas and air can be continuously combusted when the temperature exceeds preset temperatures and the gas and the air are supplied. The catalytic combustor and the gas water heater in an embodiment of the invention have the advantages that the catalytic combustor and the gas water heater are simple in structure, and various components can be reliably connected with one another; the gas and the air are catalytically combusted by the catalytic combustor, accordingly, the gas can be assuredly sufficiently combusted as compared with flame combustion modes in the prior art, energy can be saved, and environments can be protected; emission of carbon monoxide and nitrogen oxide can be reduced, the gas and the air can be combusted gently, and the catalytic combustor and the gas water heater are low in combustion noise and high in safety.