Abstract: Objective To investigate the seroprevalence of severe fever with thrombocytopenia syndrome bunyavirus (SFTSV) in human and animals in Jiangsu and provide scientific evidence for the development of prevention and control strategy. Methods A total of 2853 serum samples were collected in Lishui, Jiangning, Liyang, Yixing, Xuyi and Donghai in Jiangsu from July to November in 2010, including 1922 human serum samples and 931 animal serum samples (125 from dogs, 91 from goats, 225 from pigs, 88 from cattle, 50 from geese, 47 from mice, and 305 from chickens). A novel double antigen sandwich ELISA was conducted to detect the overall antibodies to SFTSV. The prevalence rates in different regions were compared with each other. Results SFTSV-specific antibodies were found in a total of 121 samples (4.24%), suggesting the wide circulation of SFTSV in the province. Of the 7 animal species tested, 5 species' sera, including dog, sheep, cattle, pig and chicken, were detected to be positive with the rates of 6.40%, 57.14%, 31.82%, 5.33% and 0.98% respectively. The prevalence rate in human was about 0.94%. The seroprevalence of SFTSV varied with regions and the positive correlation between human prevalence rate and animal prevalence rate was observed. Conclusion Jiangsu province is the endemic area of SFTSV infection, and it is necessary to strengthen the prevention and diagnosis of this emerging communicable disease.