This paper will discuss the unfolding of skin-panel by using the software CATIA. During the process the characteristics of integral skin-panel and the development of its unfolding were presented. Consequently, it could be seen that the structural surface of the external form could be extracted for curved surface. So the unfolding of skin-panel was able to be simplified to the unfolding of the curved surface. Main steps of unfolding the integral skin-panel in CATIA V5 software environment are stated in following parts. The measurement results of the lightening groove located in larger deformation region between surface to be unfolded and unfolded surface are compared in fig 10. And it shows that the method used in this paper meets the demand of precision and is available.