Two species in Monochamus (Coleoptera: Cerambycidae) are wellknown vector species of the pine wood nematode (PWN) in South Korea. In 2018, the surveys using sentinel logs with two Monochamus species larvae were made from early June to last September in Pinus densiflora forests of Pohang city, South Korea. The experiments were repeated 10 times in order to investigate parasitism patterns of the larval parasitoids of M. saltuarius and M. alternatus. Three plots were chose at interval distance of 20 m (0 m, 20 m, 40 m) from the edge to the center of the forests (i.e. forest depths) in one damage area of the pine wilt disease for each of three different locations. For each time of the exposure ten sentinel logs were hung along the tree heights (i.e. sentinel logs positions) (height: 0 m, 1.8 m, 3.6 m, 5.4 m, 7.2 m). As the results of the surveys six larval parasitoids in total were identified, and most abundant parasitoids were Spathius verustus and Cynopterus flavator. Analyses showed that the parasitism rate on larvae of two Monochamus species was not affected according to forest depth, but the parasitism rate was the highest in the third plot. Also the parasitism rate was the highest at 5.4 m height of a tree. Lastly, parasitisms rate on M. alternatus was higher than that of M. saltuarius.