Abstract: On the basis of that the plasticity elongation was equal for the unit length in the process of metallic materials uniform deformation,and the constriction occurred in local length,a new method was builded to acquire the percentage elongation after fracture of standard proportional sample,a short sample whose gauge length was shorter than the standard proportional sample’s was used in the method. After test,the percentage elongation after fracture which was acquired by means of the method was almost identical with that acquired by means of the method provided by GB/T 228-2002.