Abstract: In order to study the material mobile factor in the distortion zone and the influence of material parameters on sheet bulging,experimental study and simulation analysis of the sheet bulging were conducted.A bulging model of hemisphere was built and simulated on the basis of const and strain forming to study the thickness distribution.The non-uniform thickness distribution and cavity have negative influence on the formability.Direct-reverse superplastic bulging can improve the thickness distribution greatly.Porosity is decreased evidently in the bulging if back pressure is provided.