The invention relates to a multi-body simulation data interaction method for a launch vehicle. The method comprises the following steps: step (1), establishing a finite element model of the launch vehicle; step (2), performing shutdown analysis of the launch vehicle, updating or acquiring the current time sequence; step (3), performing time series analysis for each component of the launch vehicle and acquiring the status of each component of the launch vehicle through the time sequence and a preset offset value; step (4), configuring status parameters for each component of the launch vehicle, establishing interactive data cards between various components, and filling the interactive data cards with output parameters of the various components under the current status; and step (5), using a Lagrange equation of the first kind to discretize the finite element model established in the step (1) and external forces generated by the various components in the step (4) into differential-algebraic equations, solving the equations, and obtaining the displacement and load of each node in the finite element model of the launch vehicle. The multi-body simulation data interaction method for the launch vehicle provided by the invention realizes the general dynamics simulation of the launch vehicle, and realizes the calculation of the flight trajectory, attitude and load of the launch vehicle.