Abstract: The composite cylindrical grid structures exhibit quite a few features and complex structural characteristics, and its precision in manufacturing is restricted due to the curing deformation. Based on the viscoelasticity of the bismaleimide resin, high temperature creep tensile testing of the aerospace 802 bismaleimide resin was performed, confirming the existence of unrecoverable viscous flow strain after the unloading of the bismaleimide resin creep. The micro component material mechanism was revealed to reduce the process curing deformation of large composite grid structures through hot sizing. The deformation energy increment theory for composite grid structures was derived and established. The process of hot sizing load application, relaxation, and rebound of composite grid structures was simulated. The correction rebound profile of grid structures was determined, comparing with experimental results to verify the effectiveness of the deformation energy increment theory. The failure of internal stress, number of correction points and process conditions based on time temperature equivalence of hot sizing composite grid structure was analyzed. A complete process for the deformation simulation method of hot sizing deformation control for composite grid structures formed.