Abstract: It was identified that Alternaria alternata Keissler. was the pathogen of Indian Jujube black spot. The temperature range for the pathogen growth and sporulation was 10~35℃ with the optimal of 25~30℃. PDA was the optimal medium for the mycelial growth and sporulation. The pathogen could grow and sporulate in the condition of pH 3~11,while the optimal pH for mycelial growth was 6-7 and for sporulation was 5. The conidium could germinate well at 20~30℃ and pH 5~9, with the optimum of 25℃ and pH 7, the optimum humidity was RH 100% with water drop. 1% liquid of dextrose and leaf extract of Indian Jujube could hasten spore germination obviously.