One-loop on-shell and off-shell decays H → VV with VV = γγ, Zγ, ZZ are presented in this paper. The effects of one-loop on-shell and off-shell Higgs decays via Higgs productions at future lepton colliders are also then examined. We find that the impacts of one-loop Higgs decays are significant and they are should be taken into account at future lepton colliders.