The steam boiler with internal combustion three backhaul wet back quick form, can use light diesel oil, heavy diesel oil, city gas, natural gas. Burning device imported brand-name burning machine with microcomputer automatic process control systems and combustion detector protection system, equipped with high-efficiency pumps, valves, meters, and imports of soft water processor. Boilers under the protection of automatic ignition startup program, flame protection, load regulation, high and low water level control, over-temperature overpressure to achieve detection control automation. Boiler, with large water capacity and stable air pressure, is the ideal product which applied to the situation of large load change, high steam quality, low exhaust gas temperature, high thermal efficiency.