NOVELTY - An oxygen-enriched steam biomass fuel combustion improver comprises steam, biomass fuel, and co-oxidant in a weight ratio of (4-6):(3-2):(3-2). When coal burns, the combustion improver is directly compounded by a synthetic device in an on-line manner. The fuel combustion improver enters the burning coal with air by mixing and spraying process to improve combustion.    USE - The oxygen-enriched steam biomass fuel combustion improver is useful in energy-saving and environmentally-friendly method used as technical improving project of prior coal operation device and coal manufacturing device (all claimed).    ADVANTAGE - The oxygen-enriched steam biomass fuel combustion improver replaces 10-20% to save 25-35% of coal, achieves low investment and low operation cost, solves tail gas problems, and enables effective utilization of residual heat of tail gas. The combustion improver improves heat-exchange efficiency of coal operation devices.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) synthesis device of fuel combustion improver, comprising of a vaporizing-mixing-spraying gun, a pipe component, and a programmable logic control (PLC) man-machine conversation intelligent automatic combustion-stabilizing control device. The vaporizing-mixing-spraying gun is connected with the pipe component. An electric regulating valve is installed in the vaporizing-mixing-spraying gun. The electric regulating valve of the vaporizing-mixing-spraying gun, electric pump, and electric regulating valve of the pipe component and PLC man-machine conversation intelligent automatic combustion-stabilizing control device are electrically connected; and    (2) energy-saving and environmentally-friendly method, which comprises connecting the output end of the vaporizing-mixing-spraying gun in the synthetic device and air distributing pipe of the coal operation device, and installing the tail-gas dedusting bed on the duct outlet end of the coal operation device for discharging tail gas. After coal burns, the tail-gas dedusting bed is cooled, and the tail gas is desulfurized and dedusted.