Magnesium alloys have been attracting much more attentions due to its low density, high specific strength and its lightweight during the past 30 years. In this paper, the deep drawing performance of AZ31B magnisium alloy sheets at elevated temperature was studied by the experimental approach. The results indicated that the formability of the AZ31B sheets at elevated temperatures could be improved significantly. The best external forming parameters can be obtained such as heating temperature of sheet, die-punch clearance, punch fillet radius, etc. Simulating the forming process by using the numerical simulation software, we investigated the stress-strain distribution, thickness distribution and forming limit, etc. The thickness distribution by the numerical simulation agrees well with the experimental results.