The invention discloses an automatic 
pose determination method for a large-aperture element, relates to the technical field of 
engineering optics, and is used for solving the problem that the 
pose of the element is uncertain due to limited positioning precision of an element clamp on a 
machine tool. The method is technically characterized by comprising the steps that a plurality of images of an element of the current 
pose on a 
machine tool are collected and processed, translation errors and deflection errors of any point on the element relative to the calibration pose of the element under a 
machine tool coordinate 
system are obtained, the translation errors comprise X-axis translation errors, Y-axis translation errors and Z-axis translation errors, and the deflection errors comprise X-axis deflection errors and Y-axis deflection errors; and calculating according to the 
translation error and the deflection error to obtain the calibration attitude of the element. According to the method, the problem that the element pose is uncertain due to limited clamp positioning precision is solved, the calibration coordinates of the point on the element moving to any 
station on the 
machine tool are obtained, and accurate position reference is provided for subsequent positioning and repairing of the defect point.