Abstract: Macrosiphum roswomm is one of the most serious pests on Rosaceae. However, biological control of M.roswomm with Beauveria bassiana still remains unreported. The patho genicity and greenhouse control effect of B.bassiana strain isolated from M.roswomm on aphid nymphs and adults, and the survival of B. bassiana on rose leaves were studied. The results showed that, under the same conditions, aphid mortality increased with increasing spore concentration. At the spore concentration of 10⁸ spores/mL, the highest cumulative mortality was 99.3% in 5 days; the pathogenicity for adults and the third instar nymphs was much higher than the first instar nymph. Under different temperature and humidity, the highest mortality was discovered at the condition of 25 ℃, and the infection mortality rate increased with the increasing of the environment humidity; the highest infection mortality in greenhouse was 94%. These results indicated that B.bassiana has a good potential in biological control of M. roswomm.