Abstract:his paper mainly studied chitin degradation effect of different combination of several microbes(Bacillus spp. and Saccharomyces spp.)and control effect of chitin degradation liquid(CDL)on tomato(Lycopersicum esculentum Mill.)disease of root-knot nematodes by artificially inoculating Meloidogyne incognita. The results indicated that mixture of 4 Bacillus strains and a Saccharomyces strain had best degradation effect on chitin with the lowest viscosity, the highest chitinase activity. CDL could control tomato root-knot nematodes disease effectively, decrease root-knot rate and root-knot index. Therefore,control effect was 54.29 %, which was 2.58 times compared with the treatment of chitin liqiud medium. CDL could also improve the populations of bacteria, fungi and actinomycetes in soil.