Shear connection is an important process in headless rolling technology, and there are shearing, extrusion and upsetting in the deformation process. Therefore, in order to grasp the change laws of the forming load, based on the upper limit method-primitive rectangle technology and multiple regression analysis, a forming load prediction model when the reduction amount was one times the thickness of sheet metal was established, and the theoretical forming load under any combination parameters of edge width and overlap amount was solved. Then, the process experiments were conducted on the shear connection, and the primary and secondary order of influence of the process parameters on the side convex rate, the thickness percentage of head-cutting end and the load value, and the optimal scheme relative to each judgment index were obtained. Furthermore, the optimal parameter combination was obtained by establishing a comprehensive evaluation index and conducting range analysis. Finally, the experimental load was compared with the theoretical load of the established prediction model, the data of the two were similar, and the maximum relative error was less than 8%. Thus, this research has laid a theoretical foundation for the high-temperature solid-state shear connection of intermediate billets and has a certain guiding effect on the production practice.