Opisina arenosella Walker is a serious pest of palm, especially in India and Sri Lanka. It first invaded in Wanning, Hainan Province, in 2013. Since it has invaded many cities of the province of Hainan, as well as Guangdong and Guangxi, posing a serious threat to the production of palm plants in China. Bracon adoxophyesi, an important natural enemy of O. arenosella, was found in Hainan when investigating damage of O. arenosella, in November 2014. To get a better understanding of B. adoxophyesi, its morphological characteristics, distribution, and host biology were studied in order to prevent O. arenosella.