Abstract: In order to explain the occurrence regulation of Alternaria obpyriformis T.Y Zhang and be useful for the disease control, the direct-checking method, tissue isolation method and pathogenicity detection were used to study the overwinterring place and overwinterring way of Alternaria obpyriformis T.Y Zhang. The needle puncture, leaf brushing and slide attachment were used to determine the invasion and spreading ways. We detced the infection ability of Alternaria obpyriformis T.Y Zhang on 10 plant under the condation of artificial inoculation. Fungicide screen assays in lab were performed by detecting the spore germination and the mycelium growth rate. The results showed that Alternaria obpyriformis T.Y Zhang could live through the winter on plant debris with the mycelium and the pycnidiospore. The pathogen could invade host by air hole and wound. The pycnidiospore could spread through airflow. Alternaria obpyriformis T.Y Zhang could infect some leguminous plants and crucifer by artificial inoculation. Seven fungicides could obviously inhibit the mycelium growth and spore germination of Alternaria obpyriformis T.Y Zhang, while prochloraz proved to be the most effective fungicide with the inhibition rate of 84.24% and followed by those of iprodone with the inhibition rate of 67.44%