Abstract: Transmission characteristic of pinewood nematode, Bursaphelenchus xylophilus through feeding wounds of Monochamus alternatus was investigated from feeding beginning to experiment end for 50 days.The result showed that the number of nematode transmitted to pine trees was greatest about 694 nematode per sawyer at the 20th day,and was greater at the 30th day after feeding but about 100 nematode per sawyer was transmitted at before and after these day.60% of nematode was transmitted to one year old pine branches,but the number of nematode was less with increase of pine branch age.The laboratory and forest field test showed that a few number of nematode remained within the sawyer,thus it was provided one of basis for early detecting the pine wilt disease.