Currently, approximately 7 000 offshore platforms are utilized globally for marine energy exploration and production, with about 93% being fixed jacket platforms constructed by welding tubular components. Due to environmental corrosion, fatigue effects, and accumulated damage, various defects and damages are present in the structures of these marine platforms. To prevent these defects and damages from causing structural failures, a novel structural damage identification framework was proposed. This framework was established based on physical models, finite element models, testing models, and damage models, with the objectives of creating precise testing models, benchmark finite element models, and accurate damage models. Optimization theory for sensor placement was applied, objective optimization methods for minimizing frequency response function residuals and correlation coefficients were investigated, and a damage identification method was proposed based on frequency response and parameter uncertainty model updating. These approaches systematically achieved the goal of accurate damage identification in offshore jacket platform structures under the proposed framework. Finally, through a practical application case, both single and multiple damage instances in the jacket platform were accurately identified, demonstrating the reliability and applicability of the technology.