Endophytic actinomycetes were isolated from Rheum tanguticum by spread plate method. Inhibitory activities of endophytic actinomycetes were determined by dual-culture inhibition on agar plate and growth rate method. As a result, Strain 4-21with high inhibitory effect on Magnaporthe grisea was found. The strain 4-21 was indentified as Streptomyces albidoflavus according to the morphology biochemical characterization and 16S rDNA gene sequence analysis. And its potted control effect was also investigated. Strain 4-21 deserved to be developed a kind of biocontrol agent.
