Abstract: Rocket fairings are thin-walled structures susceptible to deformation during separation, potentially leading to interference with the payload. To assess separation reliability, a multi-flexible-body dynamics model of a specific rocket fairing was developed. The three-dimensional model was created in SolidWorks, and the spin-off separation process was simulated via ANSYS-ADAMS co-simulation. The results indicate that the maximum deformation, approximately 4.5 mm, occurs at the lower end of the fairing. The separation process is stable and collision-free. This study validates the structural design and provides a theoretical basis and engineering guidance for future fairing optimization.