In order to clarify the new trend of Ostrinia furnacalis under the conditions of climate warming, emergence and peak emergence progress of overwintering adults of O.furnacalis in Nenjiang county of Heilongjiang province were investigated and Trichogramma dendrolimi was released to control O.furnacalis in corn fields in three farms of Nenjiang during 2012-2014. The results showed that the peak season of O.furnacalis emergence in 2014 was earlier than that in 2012 and 2013. Compared with those farms without T.dendrolimi releasing, the rate of damage, percentage of tassel broken, residual rate of insect and boring rate were all decreased, and the yield of corn increased, and the control effect was obvious. Control efficacies of T.dendrolimi against O.furnacalis on the Daxijiang farm, the Jianshan farm and the Nenbei farm were 60%, 66.7% and 56.7%, respectively, and the yield increased by 39.1 kg, 47.6 kg and 67.0 kg per 667 m~2, respectively, compared with that without T.dendrolimi releasing. The average control efficacy in the whole Nenjiang county was 61.1% and the average yield increased by 51.2 kg/667 m~2. Releasing T.dendrolimi is of great significance to control O.furnacalis, increase maize yield and quality, recover economic losses, and protect the ecological environment.