Unearthed bronze relics are often damaged and have missing fragments. The traditional restoration method uses new hand-made parts to replace missing fragments and this approach often requires substantial efforts and time. Furthermore, these newly-attached fragments are difficult to detach and may also conceal and modify valuable information of how the original cultural relic is damaged. With the rapid progress of 3D printing’s accuracy and efficiency, as well as the application of new printing materials, 3D printing now offers multi-material composites besides just resin. Specifically, the development of metallic materials for 3D printing now allows the restoration of bronze relics to be conducted in a more scientific and effective way. In this paper, a case study of the restoration of a restructured late Shang Dynasty bronze Jia with beast-face vein from Shanghai Museum is used to explore the development of the traditional bronze relic repair skill using detachable fragments made by 3D printing, also known as detachable fitting. This new method has lesser interferences on the original properties of the cultural relics and also retains the restructuring traces, which have great research value themselves. We will see how the application of new 3D printing technologies for the restoration of bronze relics are conducted more safely and with greater precision, and achieves the delicate balance of minimal intervention to the cultural relic but yet possesses the optimal effect for exhibitions.