In recent year, there has been a growth of the manufacture and application of magnesium products. For Magnesium alloys take advantage small specific gravity and relatively high strength, shielding electromagnetic waves. However, there are so many studies to assure good formability because Magnesium alloy is difficult to form. The AZ31B alloy shows an excellent workability at temperatures from $250^{circ}C$ to $400^{circ}C$. Temperatures higher than $400^{circ}C$ are not suitable for forming of the AZ31B alloy because of heavy oxidation. Forming temperature and heat transfer of Magnesium alloy to the molds, punch velocity, friction coefficient and geometric shape of molds are important factors to forge the components successfully. The forming factors of press forging on AZ31B have been studied by finite element analysis that was done with DEFORM/3D software. By conducting a circular design which included predictive experiments, evaluation of the outcome of actual products, and process modifications, the optimum conditions were established for a forging process to manufacture a magnesium alloy camera barrel.