Abstract: The control effects of Eupolyphaga (Eupolyphaga sinensis Walker) frass and its extracts on Meloidogyne incognita were studied through laboratory assays and pot experiments, and the organic volatile compounds and oligochitosan contents in the frass were analyzed. The results indicated that the nematode immobility and mortality was significantly increased with increasing the extract concentration and treatment time. Compared with the control, egg hatching was significantly inhibited when the extract concentration was beyond 20%. Pot experiment indicated that root galling of tomato seedlings was reduced and the relative control effect was significantly improved with the increasing frass application. Meanwhile, plant height, stem diameter and leaf number of tomato increased with the increasing dosage of eupolyphaga frass. The ingredients analysis showed that the content of oligochitosan was about 4.35% and there were 9 categories and 110 kinds of volatile compounds in the frass.