Focusing mechanism is a key part of space cameras. Its dynamic performance greatly affects camera reliability. To analysis the dynamic characteristics, the focusing mechanism platform of a space camera was researched in simulation, where its entry point was the guide, and the model of the guide joint was built with the optimized tandem spring damping element in the finite element model of the focusing mechanism platform. The research obtained dynamic parameters based on the Hertzian contact theory and equalizes the rigidity of the ball screw and the coupling on the guide, and formulates the relation expression and corrected parameter. The corrected parameter was confirmed by a comparative experiment based on the variable of the coupling stiffness, thereby completing the dynamic analysis of the space camera focusing platform. Finally, the research accomplishes the dynamic simulation analysis of the focusing platform with the stated analysis method under different conditions, with a deviation of under 2%, thus demonstrating high accuracy and reliability of the analysis method.