Abstract: This study deals with the replication of Dendrolimus punctatus CPV by the cotton bollworm Heliothis armigera. The results show that D. punctatus CPV not only can be replicated by H. armigera but also can induce the virus of the host. Under the condition of average weight 0.41 g per larvae, 2.84×10 PIB were reproduced by each larva. A satisfactory result obtained after using this virus replicated on H. armigera to control D. punctatus.