Abstract:For finding the valid dosage and time in which the nematode would be killed completely, Bursaphelenchus xylophilus in the lumbers was fumigated with methyl bromide (MB), was put up respectively in the container and in the buckets made by stainless steel in the room with air-condition. Three temperatures of 13±2℃, 18±2℃, 23±2℃ and four kinds of lumber of 2.5cm×10cm×90cm,5cm×10cm×90cm,10cm×10cm×90cm,20cm×20cm×90cm were set up and every kind of lumbers was fumigated with MB of 6-7 kinds of different dosages at every temperature. The results shows that the eggs, larvae, adults of Bursaphelenchus xylophilus in the lumbers were killed totally when fumigated with MB for 24h at the dosage of 64 g/m3, the dosage over 32 g/m3 as degassing, the CT products of 1 152 gh/m3, at the temperatures of 11-15℃,or at the dosage of 56 g/m3 , the dosage over 28g/m3 as degassing, the CT products of 1 008 gh/m3, at the temperatures of 16-20℃, or at the dosage of 48 g/m3 , the dosage over 24g/m3 as degassing, the CT products of 864 gh/m3, at the temperatures over 21℃. In addition, the dosage and time is not enough to kill totally Bursaphelenchus xylophilus in the lumbers that appionted by ISPM NO.15 "The Guidelines for regulating wooden packaging material in international trade".