The invention provides a rocket-spacecraft coupling multibody system dynamics calculation test method and system. The method comprises steps that physical mechanics model transformation and topological structure construction are performed; transfer matrixes and transfer equations of various components are established, a topological structure and supplementary conditions are utilized, a total transfer matrix and a total transfer equation of the system are obtained through assembling, the system is decoupled through proving orthogonality analysis, the modal analysis theory is utilized to analyzerocket-spacecraft coupling dynamics characteristics, and inherent characteristics of the system are obtained; according to the inherent characteristics of the system, rocket-spacecraft coupling dynamics response calculation is performed; through simulation calculation, the rocket-spacecraft connected interface force condition is obtained, the force spectrum input conditions of force limit controlare obtained, and the force limit test is performed. The method is advantaged in that the rocket-spacecraft coupling dynamics response is quickly and accurately obtained, the rocket-spacecraft interface force spectrum is obtained, the input conditions of the force limit vibration test is obtained, and the force limit vibration test can be quickly and accurately verified.