Based on the combined transformation theory of the space coordinates, a scheme, which introduces three non co-linear marked points in the public areas of the adjacent subdivided shapes to digitize the whole profile, is proposed. The blending accuracy of the result data is analyzed and a verification about this is done in light-sectioning measurement system. Experimental results show that this approach can realize the subdivided shapes measuring and data registering as the features of rapid speed, high accuracy and simple operation in optical three dimensional profilometry.