Abstract: Objective To investigate the distribution of arbovirus in some areas of Gansu province, and provide evidence for the prevention and control of arbovirus disease. Methods Mosquitoes were collected in Jiayuguan, Zhangye, Jiuquan, Baiyin and Pingliang in 2008 and the viruses were isolated from them by cell culture. The isolates were identified by serological and molecular biological methods and the sequences were analyzed by bioinformatics. Results A total of 13 839 mosquitoes were collected. Six virus strains were isolated from the mosquitoes. All the strains were identified as JEV of genotype I. The homology was 87.5%-87.9% in nucleotide sequence and 96.8%-97.2% in amino acid sequence in E gene compared with the vaccine strain SA14-14-2. Conclusion GenotypeⅠJEV was isolated from mosquitoes collected in the east of Gansu province, which had close phylogenetic relationship with JEV strains isolated in Sichuan in 2004.