Vehicle-mounted gas water heater

A vehicle-mounted gas water heater comprising a casing, a water flow pipe, a heat exchanger, a combustion heating device, a smoke exhausting device, and a controller, the combustion heating device comprising a gas pipe, a gas valve, an ignition device and a burner, the water flow pipe comprising a water inflow section, a first heating section, a second heating section and a water outflow section along a water inlet to a water outlet of the water flow pipe, wherein the water inflow section is shortened, wherein the water inflow section is shortened, a heating section is rapidly heated directly by the combustion heating device, and the second heating section is heated by winding on the heat exchanger, so that when a water body flows in from the water inlet and flows out from the water outlet, formation of condensed water at the water inflow section is reduced, condensed water formed on the surface of the first heating section is rapidly evaporated, and it is difficult for condensed water to form on the surfaces of the second heating section and the outflow section.