The invention discloses a self-tightening sealing structure for connecting an initial chamber and a base, and relates to the field of self-tightening sealing structure deigns. The self-tightening sealing structure for connecting the initial chamber and the base comprises an initial chamber rear flange section, a connecting section, a base flange and bolt components, wherein the cross section of the connecting section is of a U-shaped structure; the opening of the connecting section is placed horizontally; the side wall of the top end of the connecting section is fixedly connected with the initial chamber rear flange section; the cross section of the connecting position between the initial chamber rear flange section and the connecting section is of an L-shaped structure; the initial chamber rear flange section and the connecting section fixedly connected through the bolt component at the connecting position; the side wall of the bottom end of the connecting section is fixedly connectedwith the base flange; the cross section at the connecting position of the base flange and the connecting section is a top of an ear-shaped structure; the base flange and the connecting section are fixedly connected through the bolt component at the connecting position; and according to the self-tightening sealing structure for connecting the initial chamber and the base, on the premise of ensuring good gas sealing performance, the total number of mounting fasteners is reduced, the total time consumption for mounting the fasteners is shortened, and the mounting efficiency is improved.