To match the coordinate system of measurement with CAD coordinate system,the methods for matching the measured surface and the designed surface in freeform surface inspection are studied and a multi-level matching strategy is proposed.First,the center point is defined and four corner points are searched,then the coarse matching is implemented by matching five key points to keep the measured surface and the designed surface in an approximate configuration..Secondly,the fine matching is carried out.The objective function is modified and a new optimization method is proposed to compute the configuration.Finally,simulation on a freeform surface is performed and the validity of the proposed method is verified.