Abstract: Dynamic shear properties of 603 steel were tested by the new Hopkinson bar loading technology, and the microscopic failure mechanism was analyzed. The shear stress-shear strain curves of the material were obtained at strain rates above 10⁴ s^-1, and failure parameters of the material were determined. The results show that with the increase of strain rate, the flow stress shows an obvious strengthening effect, while the failure stress increases slightly, and the failure strain decreases gradually. With ABAQUS/Explicit finite element analysis, the calculated shear stress-shear strain curves agree well with the experimental results. Fracture analysis shows that the failure mode of the material is ductile fracture, and it is influenced by adiabatic shear bands. With the increase of strain rate, the effect of adiabatic shear band is more obvious.