One species of the genus Coleopius (Hymenoptera: Braconidae: opiinae) are reported in this study. The genus Coleopius is a small braconid group distributed in the Palaearctic and Oriental regions, which has three species in the korea in current. In this study, Coleopioides postpectalis Li and van Achterberg is recognized for the first time in South Korea, which had been recently recorded from China. Descriptions, diagnosis distribution and illustration are provided