In order to solve the problem that the multi-point flexible tooling system needs to meet the engineering requirements for positioning shape variables in the process of clamping large thin-walled parts,based on the “N-2-1” positioning principle and aiming at the limitations of the uniform distribution algorithm,a method for optimizing the system position according to the principle of self generation was proposed without relying on external operators,and a multi-point positioning numerical model of large thin-walled parts was established through the finite element software Abaqus.The position optimization was carried out by first whole and then local.The results show that the optimized support point layout is reasonable and the system resource utilization rate is high;compared with the single overall location optimization,adding local location optimization can make the aeronautical thin-walled parts more easily meet the engineering requirements with the least support points;while for the local defects that cannot be supported,special circumstances need to be considered.It can adjust the corresponding support mechanism points to move in the most sensitive direction to reduce the machining deformation of the workpiece,optimize the number of support points in areas with large local deformation,so the deformation is significantly reduced compared to the initial deformation,and the adsorption pressure also meets engineering requirements.