Abstract: For determing the effectivity of different dilution times of soil amendment developed in author laboratory to rehabilitate soil in greenhouse tomato contaminated by root-knot nematodes（Meloidogyn incognita), the study was carried out with salver method to isolate, identify and record the amount of nematodes in soil and the ratio of root-knots on tomato roots of different treatments and tap water control. The results shown that among the 5 selections, the soil amendment with 125 times dilution, 500ml·plant-1 volume could control the root knot nematode effectively. With the dilution, the density of root-knot nematodes could be controlled down to 30 individuals·100ml-1soil and the root knot rate on tomato roots could be reduced down to 40%. Simultaneity, the population of beneficial nematodes, Rhabditis (Oscheius) spp. was raised up（388 indi. ·100ml-1 soil）. The result also shown that 25days is an effective interval of applying soil amendment for rehabiliting the contaminated soil in greenhouse tomato.