Abstract: The antagonism of Trichoderma longibrachiatum Against Rhizoctonia solania was tested. The result showed that Trichoderma longibrachiatum in inhibited the hyphal growth of Rhizoctonia solania,Inhibition index 1. A range of antibiotics was produced by Trichoderma longibrachiatume which was active against the hyphal growth of Rhizoctonia solania. The hyphae of Rhizoctonia solania were broken, lysed and their cytoplasm became thinning on dualculture, and the mycelial growth almost topped. The sclerotia of Rhizoctonia solania were encircled by Trichoderma longibrachiatume, and their germi-nation was inhibited. The phenomena that hyphae of Rhizoctonia solania were coiled, penetrated, lysed, broken and their cytoplasm became thinning on dualculture, were observed under micro scope.