Numerical simulation and experimental studies on cavity growth were carreed out dur-ing the bulging process of saperplastic magnesium Alloy. A three--dimensional rigid-viscoplastic finite element program has been developed and applied to predict the cav-ity radiusand volume fraction of cavity growth. The final prediction on the cavityradius and volume fraction distribution was exhibited as colorful shade pictures. Theexperimental studies wereperformed under similar conditions to the numerical oneand provided for quantitativecomparison. According to the metallography observation,the radius and volume fraction of cavity growth was quantitative achieved by usingProfound--Iron & steel software. The numerical results were in reasonable quantita-tive agreement with the experiment. Numerical simulation and experimental studies on cavity growth were carreed out dur ing ing the bulging process of saperplastic magnesium Alloy. A three-dimensional rigid-viscoplastic finite element program has been developed and applied to predict the cav-ity radius and volume fraction of cavity growth . The final prediction on the cavityradius and volume fraction distribution was exhibited as colorful shade pictures. Theexperimental studies wereperformed under similar conditions to the numerical oneand provided for quantitativecomparison. According to the metallography observation, the radius and volume fraction of cavity growth was quantitatively by usingProfound - Iron & steel software. The numerical results were in reasonable quantita-tive agreement with the experiment.