Abstract: To find a new effective and low toxic method of prevention and cure Meloidogyne incognita, the ethanol extracts from leaves of Sapium sebiferum was used for this research by toxicity test and potting experiment. The result showed that the ethanol extracts from leaves of Sapium sebiferum could highly poison Meloidogyne incognita. The treatment (concentration: 2.5g/L, treatment time: 48h), which could lead to 93.13% of corrected mortality for Meloidogyne incognita, had the strongest bioactivity among all the treatments, LC50 was 333mg/L The Meloidogyne incognita was treated with the ethanol extracts from leaves of Sapium sebiferum witch were diluted 100times,1000times and 10000times respectively. The results showed that the mean numbers of root-knots was 12.5±3.84, 20.17±4.01, 31.8±5.09, which were significantly lower than the control of 5% ethanol (62.5± 5.53), the plant height of tomato increased 28.10%,21.07%and 12.23%, and the fresh mass increased33.07% ,15.31% and 2.73% compared with the control, respectively. The ethanol extracts of Sapium sebiferum can release the harm of Meloidogyne incognita and promote the growth of plant. Further research should be done for utilizing the leaves of Sapium sebiferum to cure Meloidogyne incognita.