Present distribution areas of Myotis petax in China were Heilongjiang Province, Jilin Province, Inner Mongolia Autonomous Region, and Hunan Province. The purpose of this study is to expand our understanding of the geographical distribution of this species. In the study, eight bat individuals were captured in Nanchang, Jiangxi Province and Quzhou, Zhejiang Province from May to September 2020. The morphological and skull characteristics of the eight bats were measured by using electronic digital calipers. The mitochondrial DNA sequences of these eight bats were sequenced and deposited in the NCBI database. Then, the Cyt b and COI gene sequences of some Myotis species in the NCBI database were downloaded, and a phylogenetic tree was constructed using the maximum likelihood method in MEGA 7.0 software. The genetic distances of the Cyt b gene and COI gene of M.petax, M. daubentonii and M.laniger were calculated based on Kimura 2-parameter model. The main diagnosis characteristics of the eight bats were:small body size, head-body 42.89﹣51.41 mm, tail 35.23﹣42.62 mm, ear 11.21﹣12.68 mm, hind-foot 8.54﹣9.74 mm, forearm 40.18﹣42.22 mm (Fig. 1 and Table 1). Brain-case is lower, and upper and lower tooth rows are shorter. Rostrum is relatively wide; cranial width is greater than one-half the skull length (Fig. 2 and Table 1). Phylogenetic analysis based on Cyt b gene and COI gene sequences showed that the captured bats were well clustered with M. petax formerly discovered at home or abroad (Fig. 3 and 4) and the genetic distance was less than 2% (Table 2 and 3). The eight bats were identified to be M.petax, a new record to Jiangxi and Zhejiang Provinces. The specimens were kept in the Institute of Zoology, Guangdong Academy of Sciences at present.