The pathogens of leaf spot in odoratum was recognized as Alternaria asphodeli by separation，purification，vaccination experiments pathogens was determinated. Under laboratory conditions，the biological characteristics of leaf spot in odoratum was researched.The results showed that combined the inspection of the volume XVI ‘China Fungal Annals’ edited by Editorial Board of China Spore Flora in Chinese Academy of Sciences.Xylose was the suitable carbon source for the colony growth;KNO3 was the suitable Nitrogen source for the colony growth;25℃was the suitable temperature for the colony growth;6~7 was the suitable pH value for the colony growth;and all light conditions was suitable for colony growth.