The Type 321 prefabricated steel bridge is a classic modular, rapid-response bridge system. The bridge's overall structure is constructed from high-strength steel using precise, fully welded processes, resulting in excellent structural rigidity and toughness. Its core main girder employs a decomposable lightweight truss structure, with segments secured by a unique single-pin connection. This design not only provides components with high standardization and interchangeability but also significantly reduces the structure's self-weight, making the logistics and on-site assembly and disassembly of the entire bridge extremely convenient, enabling efficient operation even in complex terrain lacking large lifting equipment. As a highly mature emergency traffic management solution, the Type 321 steel bridge possesses strong adaptability and can be widely applied in disaster relief, temporary access roads, and other fields, depending on actual span requirements and load ratings.