Samples were collected from different positions of deceased pine infected by B. xylophilus last year during the month of March in Nanjing area of Jiangsu province. B. xylophilus were met with in the main trunks, lumbering stumps and branches of most deceased woods. Generally, a relatively high density of nematodes was found in the diseased branches in diameter from 1. 5-2. 0 cm. It is quite evident that the nematode density in branches was much more as compared with trunks. The amount of nematode in branches and trunks obviously varied with the seasonal changes.