To clarify the specific pathogentic species of brown spot in Cerasus Mill, typical infected leaves were used as materials. Traditional tissue separation method and morphological identification method were combined with analysis of multilocus of SSU, LSU, ITS, GAPDH, TEF, RPB2, Alt al and His 3 to identify the pathogen. And Alternaria alternata was identified as the pathogen of brown spot in Cerasus. The growth rate method was used to determine the sensitivity of the pathogen to 8 fungicides including 10% difenoconazole(WG), 12.5% diniconazole(WP), 2×108 cfu/g trichoderma (WP), 500 g/L isocarbazide(SC), 400 g/L flusilazole(EC), 325 g/L difenoconazole-azoxystrobin(SC), 430 g/L tebuconazole(SC), 250 g/L azoxystrobin(SC). Difenoconazole, diniconazole and trichoderma had stronger inhibitory effect against the pathogen, with the concentration for 50% of maximal effect(EC50) being 0.001 mg/L, 0.022 mg/L and 0.168 spores/mL respectively. These three fungicides mentioned above were recommended as the best fungicides for the pathogen of brown spot in Cerasus in Jiangxi Province.