【Objective】 In this study, we aimed to screen out saprophytic nematode strains that were easy to colonize and could accelerate the extinction rate of the Bursaphelenchus xylophilus population to substantially reduce the quantity of B. xylophilus in infected trees before the emergence of vector insects, thus effectively controlling the spread of the disease. 【Method】 Eight species of saprophytic nematodes were isolated from the infected trees, which were collected from epidemic areas in Anhui, Sichuan and Jiangsu Province. Eight species of saprophytic nematodes were inoculated into the infected wood blocks with an inoculation quantity of one, two and four times the number of B. xylophilus in the wood blocks. Wood blocks inoculated with sterile water were used as controls, which were cultured at 15 and 25 ℃ for 15 and 30 days, respectively. The quantity of B. xylophilus and saprophytic nematodes in the infected wood blocks were isolated and calculated. The effects of inoculation with saprophytic nematodes on the quantity of B. xylophilus were analyzed under the different inoculation amounts and different ambient temperatures. In the field, eight species of saprophytic nematodes were inoculated into the segments of the plague woods with the inoculation amount of 2.0×10⁵~2.5×10⁵ individuls, and segments inoculated with sterile water were used as the control. After 120 days, the wood samples were drilled. After 150 days, the Monochamus alternatus were captured and the wood samples around the pupae room were collected. The quantity of B. xylophilus collected was separated and counted. The changes in the quantity of B. xylophilus in the infected trees were compared before and after inoculation, and the effects of saprophytic nematodes on the quantity of B. xylophilus in the whole infected trees, M. alternatus and around the pupa rooms were analyzed.【Result】 The results from the indoor inoculation experiment showed that the number of B. xylophilus in the strain JHS2 and JHS4 treatment groups with four times and 1 times the inoculation amount on the 30th day could be substantially reduced when cultured at 15 ℃. On the 15th day of culture at 25 ℃, the reduction rate of the quantity of B. xylophilus in the strain JHS4 treatment group with three different inoculation doses were significantly higher than that of the control group. After 30 days of culture, the reduction rate of B. xylophilus in the treatment group which inoculated four times the inoculation amount of strain JHS4 was 2.9 times higher than that of the control group. Field inoculation results showed that strain JHS4 could accelerate the extinction rate of B. xylophilus in wood segments. Compared with the control group, the reduction rate of B. xylophilus in wood segments was 96%, which was significantly higher than that of the control group (74%) over the same period. Compared with CK, the quantity of B. xylophilus carried by wood samples around the pupa chambers and emerged M. alternatus in all treatment groups was often lower than that of the control group. The quantity of B. xylophilus carried by wood samples around the pupae chambers and emerged M. alternatus in strain JHS4 treatment group was the lowest, and the quantity of B. xylophilus carried by wood samples in the pupae chamber was 20 individuls per gram, and the average quantity of B. xylophilus carried by M. alternatus was 132 individuls per head.【Conclusion】 The saprophytic nematodes can accelerate the extinction rate of the quantity of B. xylophilus in infected trees and the pupae chamber, and M. alternatus. It is clear that the saprophytic nematodes have biological control potential for the pine wilt disease, and their application in the control of B. xylophilus has technical feasibility and broad prospects, which is worthy of further development and research.