The invention relates to a horizontal desulphurization device which comprises a shell portion, a filter element portion and a compressing mechanism. The shell portion comprises a barrel, a gas inlet pipe is arranged at one end of the barrel, and an openable outer cover is arranged at the other end of the barrel. The filter element portion comprises a filter element, a cavity cover and limiting codes, one end of the filter element is closed, the other end of the filter element is open, the filter element is provided with an inner wall and an outer wall, an inner cylindrical barrel and an outer cylindrical barrel which are coaxial with each other are respectively formed by the inner wall and the outer wall of the filter element, the inner cylindrical barrel is closed at a position close to the opening end of the filter element, the outer cylindrical barrel is closed at the closed end of the filter element, and a plurality of small holes are uniformly formed in the inner wall and the outer wall of the filter element; the limiting codes are arranged on the outer side of the filter element and are symmetrically formed in the two ends of the filter element; the compressing mechanism is detachably arranged on the inner side of the barrel and is positioned between the outer cover and the cavity cover, so that the filter element can be compressed towards the barrel when the desulphurization device works.