In order to solve the problem of edge diffusion existing in binary patterns, an improved 3D measurement method based on structured light was proposed. Edges with pixel accuracy were obtained by adopting an optimized preprocessing approach according to pixel neighborhood relation and logic relation of images. Considering the influence of edge diffusion for edge detection, a line-shift strategy was applied which translated line-shift patterns symmetrically based on the centerline of the last Gray code pattern’s stripes. At same time, the width of line-shift stripes was equal to the minimum of Gray code stripes width and its direction was same as Gray code patterns’. Finally, codes of the whole-field were calculated by projecting vertical and horizontal patterns respectively. Experiments show that the relative error of reconstructing a plane is 0.07% and the reconstruction time is 5.41 s, which meets the accuracy and real-time demands. Applying this method in measuring surface of mixed targets, results prove that the proposed strategy has good adaptability of different parts.