Dengue viral infections are one of the most important mosquito bome diseases in the world. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever (DHF), or dengue shock syndrome. Variation of the concentration of IL-10 has the potential to become important biomarkers to predict and assess the stage of dengue fever. In 40 patients diagnosed with dengue (DENV) infection and 30 healthy individuals as control group, we found: the concentrations of IL-10 was 4.33 pg/l in the healthy peoples and IL-10 increased significantly up to 715pg/l in dengue fever patients. The concentration of IL-10 began to rise as IgM (-), IgG (-) and to form peaks as IgG (+), which equivalent to stage of severe dengue fevere or dengue shock in clinical. The results show that the increasing concentrations of IL-10 plays an important role in the pathogenesis of dengue fever and dengue shock.