Abstract: Objectives With the development of new ship types and structural innovations, the applicability of traditional partial safety factors for verifying hull girder ultimate strength requires further validation. The conventional Load-Resistance Method, which optimizes partial safety factors based on standardized code values, exhibits limitations in both design principles and optimization methodology. It fails to account for actual failure scenarios during vessel operations and faces challenges in performing simultaneous multi-parameter optimization. Methods Based on the Global Calibration Method and incorporating the principal dimensional parameters of ship types, this study developed a multi-parameter expression for partial safety factors. A comprehensive optimization was conducted to simultaneously calibrate the partial safety factors for hull girder ultimate strength, still water bending moment, and wave bending moment, thereby establishing a multi-parameter optimization methodology that accounts for ship-type characteristics. Employing 28 bulk carrier designs as case studies, the optimization effectiveness was systematically compared between the Load-Resistance Method and the Global Calibration Method, along with evaluating the impact of introducing ship-type parameters into the optimization framework. Results The results indicate that for bulk carriers, the Global Calibration Method is superior to the traditional Load-Resistance Method in both optimization stability and result accuracy, reducing the error function by approximately 10%. The expression for partial safety factors becomes more reasonable after considering the ship length parameter, leading to a further improvement in the optimization effect by 0.3%. Conclusions In the optimization of partial safety factors for hull girder ultimate strength, the Global Calibration Method that incorporates ship-type parameters demonstrates distinct advantages, providing crucial technical support for enhancing the accuracy and reliability of ultimate strength assessment in ship structural design.