The invention relates to the field of milling, specifically a point position layout optimization method and a follow-up support head in mirror milling. It features an annular and linear sliding module to design a support head with adjustable support points. A corresponding layout optimization method is developed, starting with a coupled vibration model of the machining process. A layout optimization model is then created, with the quantity of support points and the support radius as decision variables. The goal is to minimize vibration amplitude and root mean square, constrained by structural interference and boundary conditions. The solution is achieved using a particle swarm optimization algorithm, supplemented by parameter scanning and a penalty function strategy. This invention addresses the limitations of existing single support point layouts for the mirror milling of various large thin-walled workpieces.