The invention discloses a drug controlling plant nematodes. Effective ingredients comprise natural saponin, and the natural saponin is one or more of soapnut saponin, gleditsioside, tea saponin, saikosaponin, esculentoside, ursolic acid, vulgarsaponin and begonia yunnanensis Levl. saponin. Preferably, the drug also comprises lysobacter antibioticus, possseses relatively good killing effect on plant nematodes, nematode host cerambycidae ovum and larva and the like, and additionally, is extremely excellent in controlling effect on fruit tree gummosis. The exploited drug is environment-friendly type, is increased in controlling effect, also avoids environment harm caused by usage of a large amount of severely toxic pesticides, and possesses great reality meaning for protecting our country forest resource and ecological environment and recovering economic loss.