Abstract: Objective To detect RNA and IgM antibody of dengue virus isolated from the suspect dengue fever patients and the people living nearby in Yiwu, identify the pathogen of the disease and provide technical support for the prevention and control of dengue fever. Methods Real-time fluorescence quantitative PCR was used to detect dengue virus RNA, and dengue virus IgM antibody was detected by ELISA. Results A total of 98 serum samples were collected from suspect cases, of which 57 were positive for dengue virus type 3 (58.16%). The difference on the detection of dengue fever virus was significant between the blood samples collected at 1-3 days and at 4-6 days after onset (2=6.6147, P＜0.05). The IgM was detected by ELISA for the samples with negative real time PCR results, the positive rate was 56.10% (23/41). The serum samples collected from the people living nearby were detected by ELISA, the positive rate was 22.73% (83/365). Conclusion The disease was caused by dengue virus type 3. Real time fluorescence quantitative PCR method is suitable for dengue virus-infected patients in early phase. Latent infection might occur among the people living nearby.