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茶轮斑病是中国茶园的重要病害，易造成叶片脱落甚至使植株死亡，对茶叶产量和品质造成重大影响。本研究采用组织分离法获得病原菌，通过科赫氏法则验证、形态学观察和分子水平鉴定，确定了病原种类；采用共沉淀法制备了纳米氢氧化镁 [nano-Mg(OH)2]，采用溶胶-凝胶法制备了纳米二氧化硅 (nano-SiO2) 和纳米二氧化钛 (nano-TiO2)，利用X-射线粉末衍射 (XRD) 和扫描电镜 (SEM) 对纳米材料的尺寸和外观形貌进行表征；采用菌丝生长速率法比较了3种纳米材料在质量浓度为25 mg/mL时对茶轮斑病病原菌的抑制活性。结果表明：分离所得菌株与茶拟盘多毛孢Pseudopestalotiopsis theae聚在同一分支中，自检支持率达99%，可以确定引起茶轮斑病的病原菌为茶拟盘多毛孢。所合成的nano-Mg(OH)2、nano-SiO2和nano-TiO2分别呈花瓣状、球状以及聚集状的纳米颗粒，在水中的粒径分别为4342.72、1199.05和654.95 nm，且均具有一定的团聚行为。供试纳米材料对茶拟盘多毛孢的活性高低依次为nano-Mg(OH)2 > nano-SiO2 > nano-TiO2，其中nano-Mg(OH)2的抑菌效果最佳，150 mg/mL的 nano-Mg(OH)2施用后3 d抑菌率最高，可达85.14%。研究结果可为茶轮斑病的有效防治提供新的思路和途径。“,”Tea gray blight is a severe disease in the tea-planting of China. It can cause leaf dropping easily and even plant death, which impacts the yield and quality of tea greatly. In this study, pathogenic fungus was obtained by isolating and purifying from tea leaves, and was determined through Koch’s rule, morphological and molecular characteristics. Moreover, nano-Mg(OH)2 was synthesized by co-precipitation, while nano-SiO2 and nano-TiO2 were synthesized by sol-gel methods. The size and morphology of nanomaterials were characterized by X-ray powder diffraction(XRD) and scanning electron microscopy (SEM). The mycelia growth rate method was used to determine the inhibition activity of three kinds of nanomaterials at the concentration of 25 mg/mL on tea gray blight. The results showed that the isolated strain clustered in the same branch of Pseudopestalotiopsis theae, and the support rate of self-detection reached 99%, which could determine that the pathogen was P. theae. The morphology of nano-Mg(OH)2, nano-SiO2 and nano-TiO2 were petal-like, spherical and clustered nanoparticles, and the particle sizes in the water were 4 342.72, 1 199.05 and 654.95 nm, respectively, showing certain agglomeration behaviors. The order of activity of the tested nanomaterials was nano-Mg(OH)2 > nano-SiO2 > nano-TiO2, in which the nano-Mg(OH)2 had the best inhibiting effect, and the inhibiting rate of 150mg/mL nano-Mg(OH)2 was up to 85.14% at the third day. This study results would provide new strategies and approaches for the effective prevention of tea gray blight.