A series of novel 1,2,4-oxadiazole derivatives containing 1,3,4-thiadiazole amide group was synthesized and their nematocidal activities were evaluated. The results indicated that compounds 4-methoxy-N-(5-(((3-(p-tolyl)-1,2,4-oxadiazol-5-yl)methyl)thio)-1,3,4-thiadiazol-2-yl)benzamide 4i and N-(5-(((3-(4-chlorophenyl)-1,2,4-oxadiazol-5-yl)methyl)thio)-1,3,4-thiadiazol-2-yl)benzamilde 4p showed good nematocidal activity against Bursaphelenchus xylophilus. The corrected mortality of compounds 4i and 4p at 200 mg/L was 57.1% and 60.1%, respectively, which are much better than 13.5% of the commercial seed coating agent Tioxazafen. Compounds 4i and 4p dramatically decreased the head swinging, body fluctuation,...