Abstract: To perform forming defect analysis and prediction of sheet metal parts, based on the study of numerical simulation and experimental method of sheet metal forming, a new approach which combined numerical simulation with grid experiment is proposed.The method to carry out shect meeal forming analysis with numerical simulation, and to perform forming defect analysis for specific local area with grid method is discussed in detail.By means of a practical case study, the approach for forming defect prediction and process optimization by utilizing numerical simulation method combined with experimental method is introduced. The result shows that it is an effective way to solve sheee metal forming defect problems by synthesizing numerical with experimental methods.