Abstract: Botrytis cinerea is a pathogen for a variety of economically important plants grown in and out of glass greenhouses. 12 isolates ofB. cinerea obtained from different hosts in three ecological regions of Xinjiang were artificially inoculated in in-vitro fresh leaves of 7 hosts. The respective pathogenicities of the pathogens were then confirmed by lesion size. Using RAPD method, a genetic diversity of 12 isolates was also analyzed. The results show significant difference in pathogenicity among the 12 isolates. The pathogenicity types of the isolates are divided into strong, medium and weak. With a particular reference to Hetian cucumber grey mold and Yili Tekesi tomato grey mold, pathogenicities of two isolates are strongest. The isolates which cause Akesu tomato grey mold has the weakest pathogenicity. 12 isolates are divided into 4 groups based on cluster analysis of lesion size in inoculated leaves of different hosts. Random amplified polymorphic DNA (RAPD) analysis shows that band patterns of the isolates are genetically different. 12 isolates are divided into 4 groups at a threshold of 0.65. Although no correlation exists among the pathogenicities, sampling sites and sample hosts, some form of correlation is, however, noted between the sampling site and genetic distance.