Abstract: Spaceborne optical secondary mechanisms pose significant challenges in defining random vibration test conditions due to complex load paths, limited high-frequency simulation accuracy, and insufficient experimental data accumulation, often necessitating multiple design-test iterations during product development. This study proposes an optimization method for random vibration conditions based on system-level acoustic test data. Acceleration response data from component-level random vibration tests and system-level acoustic tests were integrated to construct a frequency response function and a spectrum optimization model. Through finite element simulation and multivariate optimization, the method allows for accurate prediction of interface load conditions. This approach reduces discrepancies between test conditions and actual operational environments, avoids over-design and redundant testing due to improper loading, and enhances the test efficiency for vibration-sensitive spaceborne optical products. The proposed methodology provides a practical framework for validating vibration-sensitive aerospace components.