Halyomorpha halys(Stål, 1855) (Hemiptera: Pentatomidae), also known as Brown Marmorated Stink Bug (BMSB), is a recent invasive pest in America and Europe. It originated from East Asia such as Korea, Japan, China, and Taiwan. Genus Trissolcus (Hymenoptera: Scelionidae) which is regarded as important species for biological control of H. halys, was described 6 species previously in Korea. But biology and taxonomic character of this genus is poorly known in Korea. Herein, we report two species from Korea, T. japonicus Ashmead, 1904 and T. plautiae Watanabe, 1954. We have investigated the morphological characters and COI sequence, and conducted an experiment about parasitic preference on BMSB's egg. Morphological key and picture of two species, and result of sequence investigation and experiment will be presented.