Abstract: According to hot compression simulation data, relationships between flow stress and temperature, strain rate and strain of a Pb-Mg-Al alloy were studied through single and multiple regression, and based on experimental data, a constitutive equation of the Pb-Mg-Al alloy was created. The results show that the relationship between flow stress, strain rate and deformation temperature satisfied hyperbolic sine equation during hot compressive deformation for the Pb-Mg-Al alloy; at the same time, the flow stress constitutive equation could accurately predict the steady-state flow stress during high temperature deformation, and high temperature hot deformation of the Pb-Mg-Al alloy was controlled by activation energy.