The invention relates to the technical field of a high-speed electric railway catenary, in particular to a bus-bar middle joint for a rigid suspension catenary, and solves the problem that looseness can be easily generated among the existing catenary bus-bars under the frequent impact condition. The bus-bar middle joint has the scheme that the middle joint is provided with a pair of threaded clamp plates and screw bolts, the clamp plates are respectively arranged in clamp walls at two sides of the bus-bars and are internally connected with two bus-bars, the screw bolts pass through holes formed in the bus-bars and are used for fixing the two ends of the threaded clamp plates with the two bus-bars, an installing hole formed in each threaded clamp plate is provided with a contractive unthreaded hole section positioned at the opening part and a threaded section positioned at the bottom, the middle joint is also provided with an annular steel threaded sleeve provided with screw threads at inside and outside, the external screw threads of the threaded sleeve are suitable for the threaded section of the corresponding threaded clamp plate to be screwed in, the internal screw threads of the threaded sleeve are suitable for the screw bolts to be screwed in, the inner diameter of the contractive unthreaded hole section arranged on the each threaded clamp plate is greater than that the screw diameter of each screw bolt, and the middle joint is also provided with flat pads which sheath the screw bolts and are positioned outside the bus-bar holes.