With the rapid development of offshore oil engineering equipment manufacturing technology， modular construction has become the primary mode of equipment manufacturing. However， during the assembly and closure process of modular structural components， cumulative dimensional errors of the connecting components often lead to rework and repair， causing additional production costs. This study focuses on the precision control issues of large structural components such as flare booms during the assembly stage. For the first time， precision management technology has been applied to the assembly process of the flare boom. Through total station measurement and Eco-Block and Eco-OTS accuracy analysis software， we conducted a simulated loading analysis of the flare boom and hook. The research results show that this technology can effectively predict and control the positioning errors of the flare boom， improve assembly efficiency， and reduce economic costs of 323600 RMB， providing a new technical path for offshore modular accuracy management.