Shell structures in civil engineering are known extremely parameter sensitive, so the aim of computational morphogenesis of free-form shells is to find a rational shape which defines an ideal internal stress state. This paper sets forth a kind of computational method to generate free-form shell structures, which is a synthesis of design modelling, structural analysis and mathematical optimization. At first the design modelling of the shell is completed by non-uniform rational b spline (NURBS), then structural analysis is executed to the initial shape, at last the NLPQL algorithm which is a SQP algorithm is used for the optimization. During the optimization metamodeling is used, which involves sensitivity analysis, design of experiments and regression analysis. Several examples show the power of the approach.