The invention relates to the technical field of vehicles, in particular to a gas supply and heat preserving system of a liquefied gas vehicle. The system comprises a gas storage tank provided with a filling valve and a gas outlet valve, the gas outlet valve is connected to an engine through a material supply pipe, the gas storage tank is installed in a heating box, a coil pipe which abuts againstthe gas storage tank is arranged in the heating box, the input-output end of the coil pipe is connected to a cooling water system of the engine, the material supply pipe penetrates a hollow sleeve, the gaps between the sleeve and the material supply pipe are sealed, and a water inlet-outlet end is arranged on the sleeve and connected to the cooling water system of the engine. According to the system, civil liquefied gas is adopted as fuel, so that energy is saved, and the environment is protected; moreover, the gas storage tank and the material supply pipe are heated by means of engine coolingwater so that full gasification can be guaranteed, residues in the gas storage tank are avoided, the gas supply capability of the system is improved, and fuel supply of the engine is guaranteed; moreover, exhaust gas emission is clean, by accessing a heating system, gas which enters the engine is heated to about 80 DEG C, and the size of the gas expands 1.2 times.