Abstract: In order to find a simple,fast and accurate method for detecting woods from the Simao pine(Pinus kesiya var. langbianensis) infected by Bursaphelenchus xylophilus, the conductivity and pH value of the woods from the healthy and the diseased Simao pine were compared by physical methods in this paper. The results showed that the conductivities of the diseased and dead woods were significantly lower than that of the healthy plant. The conductivities of woods from 19 healthy plants were all higher than 45 μS/cm, those from 20 dead plants were all lower than 35 μS/cm. It was easy to distinguish the dead plants from the healthy plants by the wood conductivity. The average pH values of the diseased and dead woods were higher than that of the healthy woods. The pH values of the healthy woods were significantly different from that of the dead woods. The range of the pH value from the diseased and dead woods were much lager than that from the healthy woods. Therefore, the healthy woods could not be distinguished from the diseased wood by detecting pH value. The conductivity of stems from the 1.5yearold of Simao pine inoculated with B.xylophilus was gradually reduced as the development of disease symptom. The average conductivity of dead plant was reduced 71.8 %, comparing with the control. The pH value changed little as the development of disease symptom of inoculated plant, which was similar as the changes of pH value from infected and healthy wood in nature.