Advanced yield functions, such as Yld2004, could describe the elastic boundary of materials better than the traditional. However the balanced biaxial yield stress σb which is essential to determine the parameters of advanced yield functions is hard to measure using frequently used test equipment. This work presented an inverse method to calibrate σb of AA5182-O alloy sheet based on the Erichsen test. The maximum punch force (MPF) measured from this test was used for the inverse identification. A modification coefficient was used to drop down the simulation MPF from shell element, as the application of shell element result in higher simulation punch force. Then the relationship between σb and MPF was established based on the plane stress Yld2004. With this relationship and the real measured MPF, σb could be inversely identified. Additionally, a hydraulic bulge test was performed to verify the accuracy of this inversely obtained σb.