Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; Nankai Univ, Dept Phys, Tianjin 300071, Peoples R China
; CCAST, World Lab, Beijing 100080, Peoples R China
We study the possibilities of parametric amplification of the gravitational perturbation during reheating in single-held inflation models. Our result shows that there is no additional growth of the super-horizon modes beyond the usual predictions.