The application discloses a novel connecting flange for an energy internal combustion engine. The novel connecting flange comprises a base flange integrally formed at a gas inlet pipe joint of a collecting pipe, an intermediate sealing flange assembled with the base flange and a gas inlet pipe connecting flange mounted at the end, away from the base flange, of the intermediate sealing flange, wherein a top convex part is integrally formed in a flange hole of the base flange; an upper room and a lower room are integrally formed on the inner side of the base flange and form a T-shaped structure;internal threads are formed on the inner side of the upper room; a lower annular groove is formed in the top of the lower room in the axial direction; an upper convex part and a lower convex part areintegrally formed at the middle end of the intermediate sealing flange; and external threads screwed with the internal threads are formed outside the lower convex part. The novel connecting flange for the energy internal combustion engine is simple in structure and convenient to assemble, and the assembled flange has good mechanical sealing performance.