Abstract: The intrinsic behavior of tensile deformation was discussed on meso-level and macro-level, starting from dislocation slip and combining with the characteristics of crystal structure. It is that microscopic plastic deformation appears at different times and distributes in different areas, and occurs in all stages of the tensile stress-strain curve. The influence of strain rate on tensile properties was analyzed emphatically, and the scientificalness, difficulties and suggestions in practical operation of GB/T 228.1-2010 were also investigated from the aspects of rigidness correction and strain rate control. The results indicate that the plastic deformation in all stages of tensile test was affected by the strain rate in different degrees.