The emergency breakaway shear pin needs to be disconnected in case of emergency and make the hanging or engine separate from the wing, in order to prevent the hanging structure from damaging the wing oil tank due to the rebound of the ground during the emergency landing. In this paper, stainless steel material shear pin is taken as the research object, and the mechanical properties of the material are tested by the test method. According to the test results, the elastic-plastic constitutive model of the shear pin is established, and the double shear simulation analysis of the breakaway pin under two different diameter thickness ratios is carried out according to the constitutive model. The results show that under the double shear condition, with the increase of applied load, the shear stress on both sides of the pin increases continuously; the larger the inner diameter is, the greater the shear strength at the moment of failure is, the greater the failure displacement is.