Abstract: Aiming at the problem of lightweight design and simulation for shell-structure models,this paper proposes a heat diffusion based lightweight method for shell-structure automobile models.By taking advantage of 3D printing on personalization,we establish a complete system consists of numerical simulating,3D printing and the engineering validation.Firstly,an analysis and extraction of features are performed on the model.Secondly,given a feature constraint and force conditions(under external force),we obtain an initial model whose thickness is corresponded to the simulated value in the heat field that is used to simulate the stress distribution.Thirdly,a test model is printed using the 3D printer for the engineering validation.The required thickness can be approximated better by adjusting the heat diffusion according to results of the engineering validation.Finally,an optimized model that satisfies all the conditions can be obtained using an iterative process.Experiment results show that the actual weight loss can reach 30%,and meanwhile,it greatly shortens the development cycle of shell-structure automobile models,hence,the proposed method is effective and efficient.