In view of the problem that the surface of the wing skin drilling is irregular and the thickness of the workpiece in different positions is uneven, the countersunk screw in different positions cannot sink into the surface completely, based on the recognition algorithm of the intersection feature of the main base surface, the geometric information extraction method was introduced, and a method of automatically determining the punch depth according to the different points of the camber surface was proposed. Thus, the screw head can completely sunk in the overall dimension. Under CATIA/CAA platform, by utilizing the Visual Studio platform, the intelligent countersunk head function was developed, which made up for the shortage of the equal depth countersunk function that could only be drilled on regular surface before. The results of the example show that the method can be better applied to engineering application, to meet the actual production requirements and improve the production efficiency.