The invention discloses a fuel supply system which comprises a pure hydrogen storage container, a pure oxygen storage container, a first pressure regulator, a second pressure regulator, an engine combustion chamber, a power generator, a storage battery, a hydrogen/oxygen fuel battery, a water storage tank, an electrolytic bath, an exchange film, a first pressurizer and a second pressurizer, wherein the pure hydrogen storage container is used for storing and supplementing pure hydrogen; the pure oxygen storage container is used for storing and supplementing pure oxygen; the first pressure regulator is used for regulating the pressure and the flow of output pure hydrogen and pure oxygen; the second pressure regulator is used for regulating the pressure and the flow of output pure hydrogen and pure oxygen; the engine combustion chamber is used for receiving pure hydrogen and pure oxygen and igniting so as to combust to generate the power; the hydrogen/oxygen fuel battery is used for receiving pure hydrogen and pure oxygen so as to generate chemical reaction to generate the power; the exchange film is used for separating and purifying hydrogen and oxygen generated by the electrolytic bath into pure hydrogen and pure oxygen; the first pressurizer is used for conveying separated and purified pure oxygen to the pure oxygen storage container to be stored up; and the second pressurizer is used for conveying separated and purified pure hydrogen to the pure hydrogen storage container to be stored up. The fuel supply system has the advantages of diverse fuel, clean gas discharge, low noise, little environment pollution, high reliability and the like, and is easy to maintain.