Abstract: In order to reveal the pathogenic mechanism of cell wall degrading enzymes (CWDEs) in tobacco target spot disease pathogen, Rhizoctonia solani (R. solani) was studied in terms of their activities, production condition and damage effect. The results showed that R. solani in tobacco could produce pectinase and cellulase both inside and outside a living body. Outside the living body, the activities of polygalacturonase (PG) and pectin methylgalactuionase (PMG) were the highest; inside the living body, the activities of carboxymethyl cellulase (Cx) and β-glucosidase were the highest, and the enzyme production ability of strains with strong pathogenicity was stronger than that of strains with weak pathogenicity. Cx and β-glucosidase cultured for 10 days reached their highest activities, while PG, PMG, polygalacturonic acid transeliminase (PGTE) and pectin methyltranseliminase (PMTE) cultured for 12 days reached their highest activities. The appropriate conditions for producing CWDEs were: temperature 25℃, pH value 5-6, still culture in the dark. The CWDEs in R. solani could obviously damage tobacco leaves, the damage caused by a mix of said enzymes was more serious than that caused by a single enzyme, and the damage caused by pectinase was more serious than that caused by cellulase.