Abstract: The impact test standards ASTM E23-16b and EN 10045-1:1990 require the striker radius of 8 mm and 2 mm, respectively. To study the influence of the striker radii on the impact test results, a series of temperature impact tests were performed on SA508Gr.3Cl.2 steel based on these two standards, and the fracture morphology was also observed. The results show that the striker radii have effect on the impact absorbed energy, lateral expansion value, percent shear fracture and ductile-brittle transition temperature. In general, in toughness and brittleness zones, that is within the range of low energy and high energy, the test results with striker radius of 2 mm were less than those with striker radius of 8 mm, and in the range of ductile-brittle transition temperature there was no significant size relationship.