Abstract: In the latest version of impact test standards, the impact pendulum blades of R₂ and R₈ specifications were accepted, but the data difference between them has been controversial. Taking standard samples supplied by three supplier as test objects, the influence of two radius of pendulum blade on impact test results was studied. The results show that for V-notched low energy samples, the difference between R₂ and R₈ blades was not higher than effect of the uniformity of the standard samples. The experimental results were related to the properties of the samples themselves. For arc samples, the impact absorption energy measured by R₈ blade was higher than that measured by R₂ blade, and the better the toughness of the samples were, the greater the difference between the two were.