Abstract: To probe into the causes for the death of pines in Vietnam, a couple of withered Pinus species like Simao pine(Pinus kesiya Royle), masson pine(P. massoniana Lamb)and Pinus latteri (P. merkusii Jungh et de Vries)from Lam Dong Province, Thua Thien-Hue Province, Quang Ninh Province were investigated. Nematodes were isolated from the wood xylem of 52 dead, dying and healthy pine individuls, and classified according to the morphological characteristics. The survey results showed that, during the process of dying, the needles of the pine tree crown part lost luster at early stage, then gradually turned into yellow followed with red color change and needle dried out, finally the whole crown of the pine turned into brown or reddish brown and the whole pine tree died, while the needles were drooping but not falling down in the first year. With the development of the disease, the rosin secretion gradually reduced and eventually stopped, the longicorn beetle made the oviposition cut marks on the trunk, the emergence holes appeared when the tree dead. Generally, the Thailand bursaphelenchus(Bursaphelenchus thailandae), the cantilever bursaphelenchus(B. gerberae), China umbrella aphelenchoides(B. sinensis), trees bursaphelenchus(B. silvestris), Tuscany bursaphelenchus(B. tusciae), Lainuerfu bursaphelenchus(B. rainulfi), spruce bark beetles bursaphelenchus(B. rufipennis)and bursaphelenchus nematode undetermined species(B. sp.)were identified in this study. We didn't find, the pine wood nematode(B. xylophilus)during the investigation.