NOVELTY - A fuel system includes a hydrogen generation system (1) having a medium hydrogen-rich mixed gas tube (102) connected with an inlet of hydrogen buffer tank, and a medium waste gas tube (103) connected with a fuel recovery system. A hydrogen-rich mixed gas tube of hydrogen buffer tank is connected with an engine. Exhaust gas of engine is connected with a mixed burner (5) through an exhaust gas pipe (301). Pre-heating fuel in the fuel recovery system is conveyed into the hydrogen generation system through a fuel tube (100).    USE - Fuel system for on-board hydrogen generation engine and device.    ADVANTAGE - The fuel system has high hydrogen yield rate, no scale formation, long post driving length and low production cost; and produces gas with stable components.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a hydrogen generation system in which hydrogen-rich mixed gas catalyzed and transformed from fuel is conducted from a catalytic reaction chamber (002) through a tubular gas-liquid separation film (m) integrated in compact on-board hydrogen generator (c), and water for fuel catalysis, reforming and hydrogen generation is the regeneration water from gas exhaustion of engine; and    (2) a gas-liquid separation film formed of porous stainless steel, ceramic, or metal (including alloy) inorganic composite, and having a length equal to an axial length of three catalytic reaction chambers, a flux of hydrogen-rich mixed gas of greater than 80 m3/m2-hour-bar, and a hydrogen-rich mixed gas/liquid fuel separation coefficient of greater than 5000, in which hydrogen content of hydrogen-rich mixed gas is greater than or equal to 40 vol.% (dry basis).    DESCRIPTION OF DRAWING(S) - The drawing is a sectional view of a fuel system.    Inlet gas chamber (001)    Hydrogen generation system (1)    Catalytic reaction chamber (002)    Hydrogen-rich mixed gas chamber (003)    Exhaust gas chamber (004)    Desulfurization chamber (005)    Mixed burner (5)    Fuel tube (100)    Exhaust gas tube (101)    Medium hydrogen-rich mixed gas tube (102)    Medium waste gas tube (103)    Exhaust gas pipe (301)    Fuel pre-heating heat exchanger (a)    Pre-heating fuel tube (a01)    Fuel evaporator (a1)    Regeneration water tube (a02)    Regeneration water evaporation heat exchanger (b)    Regeneration steam tube (b01)    Regeneration water evaporator (b1)    On-board hydrogen generator (c)    Regeneration water pump (d)    Gas-liquid separation film (m)