Green manufacturing is very important to reduce the environmental pollution and the material loss. Porthole extrusion is a useful process for producing a long aluminum cylinder tube. In this process, the initial billet is homogenized at a high temperature for a long time to improve the extrudability. The homogenization process is not only a high energy-consuming process but also a high pollution process. Therefore, an alternative process is needed for green manufacturing. In this study, a new porthole extrusion for green manufacturing was developed to reduce the energy consumption through the convergence of the homogenization heat treatment process and the billet pre-heating process. The flow stress of the initial billets with the conventional homogenization heat treatment process and the proposed converged process were obtained through the hot compression test. FE analysis was performed to assess the application of the proposed method. Through FE analysis the extrusion load, material flow, temperature, effective strain, and welding pressure were compared with each other. Finally the porthole extrusion experiment was carried out based on the result of FE analysis. As a result, it can be seen that the aluminum cylinder tube without defect can be produced by applying the proposed green extrusion process.