Abstract: In order to strengthen the biological control of Ostrinia furnacalis in sorghum field and further improve the yield and quality of sorghum,the control effect of Trichogramma dendrolimi on Ostrinia furnacalis was investigated by using the comparative experiment method of different amount of wasps according to the occurrence regularity and damage characteristics of corn borer on sorghum,and the optimal time and quantity of Trichogramma dendrolimi were determined.The results showed that Trichogramma dendrolimi could effectively control Ostrinia furnacalis in sorghum field.Trichogramma dendrolimi was released at the time of 1-2 eggs pods per 100 plants in the field.The amount of Trichogramma dendrolimiwas 35 000 per 667 m~2,twice,15 000 for the first time,and 20 000 for the second time 7 days later,with 3 points per 667 m~2.The control effect was 65.29%in autumn.Trichogramma dendrolimi has good control effect and low cost,so it has great application value in production.