cylinder head is one of the largest and the most complex parts in an engine[1] . Application of CAD is greatly limited due to the complexity of its structure. Today,the development of CAD for the cylin?der head system is a field yet to be unfolded in China. Based on the I-DEAS Master 6.0，utilizing fully func?tions of the Open ideas and applying techniques of parametric modeling based on features,object orientation and database techniques,a CAD system for the cylinder head of high-speed heavy-duty vehicular diesel en?gine is developed. It is an integrated system involving 3D-modeling, 2D-graphics, FEM analysis and Opti?mization. In this way a software environment for the design of cylinder head is established.