Flat receptacle, which is used in extruding the large aluminum profiles, is in harsh work conditions. Due to the irregularity of inner hole of flat receptacle, inconsistent resistance of shrinking fitting affects the inner hole within which nonuniform deformation occurs. If the nonuniformity exceeds the specified dimension accuracy, tiresome work including mould repairing and structure optimization has to be done. ANSYS is used to simulate the flat receptacle. It is shown that the maximum stress appears in the arc area of inner hole. Therefore, we present one new method using the preloaded layer with changeable shrinkage to replace the preloaded layer with uniform shrinkage. Considering the processing and assembling factors, we adopt the elliptical outer layer and circular inner layer as the new structure. Then the optimizations of flat receptacle with uniform and changeable shrinkage are implemented using the optimizing module, receptively. The optimized results show the maximum equivalent stress in the corner of inner-hole decreases about 5.47% if adopting the changeable shrinkage. The numerical simulation results show that the feasibility of changeable shrinkage and elliptical preloaded layer.