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Numerical simulation method was used to study material flow law of magnesium alloy variable curvature panel formed by progressive bending technology (PBT). The experimental is completed, and several types of magnesium alloy variable curvature panel are obtained. The curvature radius of panel range is from 205.7 mm to 72.56 mm. The suitable process parameters for progressive bending of magnesium alloy variable curvature panel are determined. The results show that curvature radius of panel is related to amount of press height. As press height increases, radius of curvature of panel decreases. With increase of press height, absolute deviation between simulation results and experimental results decreases, and relative error increases. With increase of curvature radius of panel, absolute error increases and relative error decreases. For internal grid panel of magnesium alloy, and maximum relative error is 5.22%. For outer grid panel of magnesium alloy, and maximum relative error is 5.51%. The generatrix straightness method was used to evaluate the degree of concave defects on surface of magnesium alloy panel. With the curvature radius of panel decreased, the generatrix straightness deviation increased, and the generatrix straightness coefficient increased. When curvature radius of panel is 72.56 mm, the maximum deviation of generatrix straightness is 0.083 mm, and the corresponding maximum value of generatrix straightness coefficient is 0.237%.