Aiming at the general launching platform of a certain type of target missile, the coupling dynamic characteristics of rotation and pitch of the platform under the action of swing load are studied. The coupling dynamics of rotation and pitching of the original land-based launch platform was extended to the sea platform, and the motion characteristics and coupling dynamics of rotation and pitching of the launch platform were analyzed under the 6-level sea state of a ship. The 6-level sea state was equivalent to the equivalent acceleration along the 3-coordinate system, and the simulation analysis of the target missile general launch platform under the sea state was carried out based on ADAMS. The simulation results show that the study has certain guiding significance for the structural strength and motion law of the launch platform under complex sea conditions.