Abstract:The Dengus viruses were isolated from the acute stage serum samples of patients with Dengue fever by means of cell culture isolation method,in which C6/36 monolayer cells were inoculated with serum samples and the CPE was observed at a 5-7 days interval. The serotypes of the isolates were determined by immunofluorescence assay with serotype-specific monoclonal antibodies. It was demonstrated that 6 strains of Dengue virus typeI were successfully isolated from 10 acute stage serum samples of patients with a isolation rate of 60%,and this result was accordant with that of RT-PCR.