It has been found more than 100 species of mosquito-­borne viruses circulating around the world, and these viruses could cause several severe diseases in both animals and humans, which is a public health issue raising worldwide concern. For a long time in China, Japanese encephalitis and dengue fever were the mainly mosquito­borne viral diseases. While, recently, the epidemic of West Nile virus and Tahyna virus and related viral diseases has been found in China. West Nile virus was isolated from the mosquito samples collected in Xinjiang Uygur Autonomous Region and a large number of serological results provided the evidence that diseases caused by West Nile virus infection existed in the local area and also, epidemic of viral encephalitis once occurred due to West Nile virus infection. Besides, Tahyna virus was isolated from the mosquito samples collected in Xinjiang Uygur Autonomous Region, Qinghai Province and Inner Mongolia Autonomous Region, and the virus circulation in nature and the prevalence of clinical infections were also found. West Nile virus and Tahyna virus and those related infectious diseases found in China offer new challenges for the prevention and control of vector­borne viruses and vector­borne viral diseases.