Abstract: To solve the problem of defects such as folding and insufficient filling easily occurring during the forging process of aluminum alloy spacer bar frames, this study focuses on the optimization of forging billet design for a specific model of 6082 aluminum alloy twin-split spacer frame. Based on a cylindrical bar, three different preform design schemes were proposed. The material flow behavior and defect formation mechanisms during the forging process were systematically analyzed using finite element simulation software. The simulation results indicate that scheme 1 (direct forging) led to significant folding defects in the annular feature region. Scheme 2 (forging after flattening) resulted in folding defects transferring to the edge of the rounded corners. Scheme 3 (forging after bending and flattening), however, effectively improved the material flow path, ensuring complete die filling and successfully suppressing the occurrence of folding defects. Comprehensive comparative analysis shows that the forgings produced by scheme 3 meet the product qualification requirements. This billet design approach provides an effective reference for the forging process development of complex-shaped parts and holds significant engineering application value.