The maximum equivalent plastic strain (EPSmax), which can be achieved in the gauge area of a cruciform specimen during biaxial tensile tests, is limited due to early fracture on the cruciform specimen arm. In this paper, a theoretical model was proposed to determine the factors related to the EPSmax of a cruciform specimen following the ISO16842 standard. Biaxial tensile tests were carried out to verify the theoretical analyses. Results show that the material strength coefficient (k) has little effect on EPSmax, and EPSmax increases with the increasing of the material hardening exponent (n) and the cross-sectional-area ratio(c) of the arm region to the gauge region (α). It is found that the applied load ratio has an effect on the EPSmax, and the EPSmax decreases as the load ratio increases from 0:1 (i.e. uniaxial tensile) to 0.5:1 (i.e. plane strain) and then increases as the load ratio increases to 1:1 (i.e. balanced biaxial tensile).