An optical mapping method for acquiring CAD model of turbine blade and its tiny holes is proposed. Firstly, making use of Digital Structure Light (DSL) 3D scanner of small field of view, the multiple profile segments of the blade are measured and integrated into the whole profile through alignment. Secondly, some high accurate cylinder gauges of proper diameter are inserted into tiny holes and point cloud of gauges are measured and integrated into the blade profile. Finally, NURBS surface is fitted by point cloud of the blade and the cylinder surfaces are fitted by point cloud of gauges. The positions of tiny holes are intersections of cylinder axes and NURBS surface, and the normal orientations are cylinder axes. The method measures gauges rather than directly tiny holes through transferring measurement object. The high precision and reliability of the reconstruction model are reached by increasing sample density of measuring point cloud. The mapping result shows, the fitting error of NURBS surface and cylinder surface are both 0.104 mm.