At present,there are very few reports on the inhibitory effect of Camellia oleifera polyphenols on plant pathogenic fungi.In this paper,the best extraction method of polyphenols was determined by analyzing the extraction rate of polyphenols in C. oleifera leaves at different conditions,and the inhibitory effect of different concentrations of polyphenols on common plant pathogenic fungi were analyzed and the bacteriostatic mechanism was studied.The results showed that after a liquid to material ratio of 1∶30,ethanol concentration of 60%,and ultrasonic treatment for 60 minutes,the extraction rate of polyphenols was the highest,reaching 14.01%.The addition of 0.80 g β-cyclodextrin in 1.0 g leaves could increase the extraction rate to 22.92%.The polyphenols at concentration of 10% had a certain inhibitory effect on Curvularia lunata,Fusarium pseudograminearum,Alternaria alternata,Corynespora cassiicola,Verticillium dahliae,Botryosphaeria dothidea and Fusarium oxysporum f.sp. momdicae.The inhibition rate to Verticillium dahliae was the highest,which was 78.52%.Polyphenols had great impact on the metabolic process of soluble proteins in plant pathogenic fungic,which is a self-regulation mode of plant pathogenic fungic in adapting to chemical stress.The results of this study provide a theoretical basis for the comprehensive development of C. oleifera and the green prevention and control of plant diseases.