The invention relates to a biogas supplying system and particularly relates to a production method of a biogas supplying boiler and a system device thereof. The system device is characterized in that a gasifying furnace is internally provided with a matched gasifying fan with the corresponding type and is connected to burning equipment by a gas pipeline; a tar collecting tank is arranged at the front of the burning equipment; the gas pipeline keeps a downward-inclination angle, wherein the end connected with the gasifying furnace is higher, and the end connected with the burning equipment is lower; biogas discharged from the gasifying furnace is cooled to be 100-250 DEG C after passing through a cooling device and then is conveyed to a special biomass gas burner for burning. The production method and the system device have the advantages that water vapor and tar substances carried in the conveying process of the biogas can form a layer of liquid membrane at the positions of a gas pipe wall, a fan volute and an impeller and the like, and due to the existence of the liquid membrane, a conveying pipeline and conveying equipment have the characteristics of corrosion resistance, wear resistance, insulation and self cleaning and the progress in the aspect of long-term, continuous and stable operation of the pipeline, a fan and the burning equipment is great.