In this study, structural durability enhancement of the fuel tank support bracket for a KMTV was investigated. During the component-level durability test, a fracture was observed at approximately 250,000 cycles under a target of 570,000 cycles, indicating the need for structural reinforcement. To address this issue, a reinforced bracket was designed. Durability analysis was conducted using finite element modeling, with only the bracket geometry changed while maintaining consistent boundary condition. The analysis results showed that the reinforced design achieved a durability life approximately 15 to 16 times longer than the original bracket. These findings demonstrate the effectiveness of the reinforcement design in significantly improving fatigue life under repetitive load condition. Future work includes vehicle-level endurance testing to validate the correlation between simulation results and actual performance, as well as further refinement of the design based on various operational conditions.