The invention discloses an in-orbit spacecraft internal device installing structure capable of quickly being disassembled and turned over. The in-orbit spacecraft internal device installing structurecomprises a plurality of horizontal plates, a plurality of middle vertical plates, a plurality of side vertical plates, a plurality of cover plates and a plurality of vertical beams. The plurality ofhorizontal plates are arranged side by side, every two adjacent horizontal plates are connected with the middle vertical plates, and every two adjacent horizontal plates are equally divided into two space units by the middle vertical plates, the side vertical plates are connected to the side faces of the space units, and the cover plates are connected to the front faces of the space units. One side of each middle vertical plate is connected with the corresponding vertical beam, and one side of each side vertical plate is connected with the corresponding vertical beam. The vertical beams are connected with connecting frames in a sealed cabin. The in-orbit spacecraft internal device installing structure capable of quickly being disassembled and turned over has the advantages of large installation space, attractive appearance, safety and being capable of being quickly disassembled and repaired in orbit.