The invention relates to a closure section steel shell of a turning continuous beam. Influences of construction of a turning construction closure section on an existing line below are severe. According to the closure section steel shell, a shell body exactly the same as the outer surface of a beam body in shape is arranged and connected to the end portion of the beam body of the turning continuous beam. The shell body comprises a bottom plate and side plates which are arranged on the two sides of the bottom plate and extend upwards, the inner wall of the shell body is provided with a transverse partition board vertical to the bottom plate and the side plates in a welded mode, the transverse partition board is a bent long-strip-shaped plate, the two faces of the transverse partition board are provided with longitudinal reinforcing ribs vertical to the transverse partition board, a connection steel plate is welded between the shell bodies of the end portions of the two turning continuous beams to be closured, the connection steel plate is a bent plate, the shape of the bent plate is the same as that of the shell bodies, and the connection steel plate and the shell bodies at the two ends constitute a sealed operation whole. The closure section steel shell serves as an outer die, bears self-weight of a beam section and construction load and forms a combination beam with concrete to be involved in structure stress, meanwhile, construction of the closure section is carried out in a steel box which is completely sealed, and influences of construction of the closure section on the existing line are greatly reduced.