Abstract:Nine strains of Beauveria bassiana separated from Chilo suppressalis Walker were studied by comparing in sporulation, vegetative growth, spore germination rate and pathogenicity for 3rd instars larvae of the rice stem borer the Chilo suppressalis. The results showed that the strains HN1, YJ2 were recognized as the better strains for its high sporogenous ability(19.03×107spores/cm2, 17.30×107spores/cm2) on PDA medium, high germination rate(93.67%, 91.08%) in 14h, fast vegetative growth(2.822mm/d, 2.748 mm/d) and high mortality rate(97.33%, 96.00%), which were significantly higher than those of the CK strains. HN1, YJ2 strains could potentially be used in bio-control.