The realization of the data exchanges between the reverse engineering system and CAD / CAM system is by Graphics Interchange standards, of which the initial graphics exchanges specification IGES is one of the important ways that data exchanges in systems. At first, the paper introduces the structures of the five parts that composes the IGES file. Secondly, it also introduces the meaning of the parameters that the rational B-spline surface in IGES and gives the method to identify and extract IGES surface data in the reverse engineering system. At last, it uses the OpenGL graphics system to show the surface data. Then, the exchanges of the surface data between the systems can realize easily by the method.