We appreciate Bai's comments on earlier work the contribution of notch effect to the early occurrence of ductile-brittle transition of Zircaloy-4. Bai comments that in addition to notch effect, both strain rate effect and different hydriding temperature may contribute to the hydrogen content at which ductile-brittle transition could occur. We reply to two aspects of his comments, the effects of strain rate and of hydriding temperature on the ductile-brittle transition. In summary, through a comparison of the results of tensile tests between smooth and notched specimens, we believe that the occurrence of ductile-brittle transition at a lower hydrogen content for notched specimens than that for smooth specimens is mainly due to notch effect. We agree with Bai's viewpoint that the experimental conditions under which the hydriding and testing were performed should be considered when one compares the results from different authors.