Abstract: Membrane reflectarray has great advantages in realizing the requirements of high gain and lightweight for spaceborne antennas. It has low areal density, high stowage ratio and high electromagnetic design freedom. However, there is no large-aperture membrane reflectarray antenna on orbit, since large deformation and vibration of the membrane caused by multi-physical fields such as space thermal environment, light field, electromagnetic radiation, particle radiation, gravity gradient will seriously affect the electromagnetic performance of the antenna. In order to verify the feasibility of large-aperture membrane reflectarray antenna, the electromechanical coupling model is established. The influence of reflectarray patch error and feed error on the electromagnetic performance of the antenna is analyzed, and the influence of membrane deformation and vibration on the gain and sidelobe level are investigated, which provide reference for the on-orbit error analysis of the antenna.