For isothermal local loading process by means of partitioned die, the partition at a rib is generally adopted in order to reduce the disadvantageous influence of loading area on unloaded area. In the local loading process, some metal (flow-into metal) in loading area flow into unloaded area due to the local loading characteristic. The distribution of the metal flowing into unloaded area plays an important role in analyzing the forming process, controlling the metal flow, and improving the forming quality. The distribution of flow-into metal coming from loading area is mainly determined by the shape of the unloaded area and the geometric parameters near the die partitioning boundary. If the unloaded area is a formed area then some of the flow-into metal will fill the cavity of partitioning rib. A predicted model for the ratio of flow-into metal distributed to cavity of partitioning rib has been established by using partial least squares regression. The numerical simulation result indicates that the analysis on distribution of flow-into metal and the predicted model are reasonable.