The utility model discloses a desulfurization and dust removal device used for a small coal-fired furnace. The desulfurization and dust removal device comprises a casing and an inner cover, wherein a smoke inlet is formed in an upper portion of a side wall of the casing, the inner cover is arranged in the casing, a smoke outlet is formed in an upper portion of the inner cover and penetrates through a top wall of the casing, and an outer wall of the smoke outlet is hermetically connected with the portion, in contact with the outer wall of the smoke outlet, of the top wall of the casing. Alkaline cleaning water is contained in the casing and has a liquid level, a bottom edge of the inner cover has a bottom edge height, and the liquid level is higher than the bottom edge height of the inner cover. The desulfurization and dust removal device used for the small coal-fired furnace can achieve the effect of cleaning smoke at a low cost.