Human cytomegalovirus (HCMV) infection can be accelerated by intracellular and extracellular hydrogen peroxide (H2O2) stimulation, mediated by the activation of the p38 mitogen‐activated protein kinase (MAPK) pathway. However, it remains unknown whether host gene expression is involved in H2O2‐upregulated HCMV replication. Here, we show that the expression of the host gene, cyclophilin A (CyPA), could be facilitated by treatment with H2O2 in a dose‐dependent manner. Experiments with CyPA‐specific siRNA, or with cyclosporine A, an inhibitor of CyPA, confirmed that H2O2‐mediated upregulation of HCMV replication is specifically mediated by upregulation of CyPA expression. Furthermore, depletion or inhibition of CyPA reduced H2O2‐induced p38 activation, consistent with that of H2O2‐upregulated HCMV lytic replication. These results show that H2O2 is capable of activating ROS‐CyPA–p38 MAPK interactions to enhance HCMV replication.