An enzyme-linked immunosorbent assay (ELISA) method was developed for the detection of neutralizing antibodies against severe fever with thrombocytopenia syndrome virus (SFTSV). Vero-E6 cells in a 96-well micro-plates were challenged with SFTSV first, and then subjected to the treatment with an anti-nucleocapsid protein (SFTSV-NP) monoclonal antibody at different concentrations. The 50% tissue culture infective dose (TCID₅₀) was calculated with Reed-Muench method. 10 double serum samples collected at two different stages of infection were subjected to the assay. 8 specimens demonstrated higher (>4 times) antibody levels in the recovery phase than that in the acute phase. In conclusion, the established ELISA method is specific, operation friendly and with an application potential for clinical research.