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[ Objectives ] The purpose of this study was to screen resistant cultivars for black spot disease resistance breeding. [ Methods] The tissue block separation method was used to separate and purify the pathogens of black spot disease. The morphological identification of pathogenic conidia was observed by microscope, and then molecular level identification was used to fungal 18S rDNAITS sequence. Based on the identification results of pathogens of black spot disease, 38 cultivars chrysanthemum for tea were inoculated and identified. The characteristics of leaf epidermal trichomes and stomata structure were observed by scanning electron microscope. [ Results] The strains of Fl6 and F20 were isolated from black spot disease leaves of ' Fubaiju', and both two strains were Alternaria alternate. The pathogenicity test showed that both Fl6 and F20 could cause black spot disease of chrysanthemum for tea, and both of them had strong pathogenicity and no significant difference in pathogenicity. The identification results of 38 cultivars showed that there were 11 resistant cultivars ( accounting for 28. 95%), 22 moderately susceptible cultivars ( accounting for 57. 89%), and 5 susceptible cultivars( accounting for 13.16%). By further comparing the differences in leaf structure characteristics of typical resistant and susceptible cultivars, the results showed that the epidermal trichomes density of resistant cultivars was generally greater than susceptible cultivars and the stomatal density was less than that of susceptible cultivars. [ Conclusions] This study screened out some resistant cultivars to black spot disease and found that the epidermal trichomes and stomatal density were related to their resistance. It was also the first time to find that Altermaria alternata could cause chrysanthemum leaf spot disease. [ABSTRACT FROM AUTHOR]