The invention discloses a mounting assembly for long rod type test equipment for an engine. The mounting assembly for the long rod type test equipment for the engine comprises: sealing components, wherein each sealing component is mounted on a through hole of a layer of an outer casing wall, and a long rod passes through the through hole of each sealing component; a casing structure, wherein the casing structure is configured to pass through a through hole of an inner casing wall, the casing structure is provided with a through hole, the long rod passes through the through hole in the casing structure, and one surface of the casing structure is attached to a displacement mechanism; and a mounting bracket set, wherein the mounting bracket set is mounted on the inner casing wall, one surfaceof the mounting bracket group is attached to a surface, opposite to the surface attached with the displacement mechanism, of the casing structure, and the mounting bracket set is connected with the casing structure and the displacement mechanism. The mounting assembly for the long rod type test equipment for the engine can fix the long rod type test equipment and the displacement mechanism thereof to the outside of the engine in the state of the whole engine.