Objective to compare the three methods of ELISA, IFA and WB in the detection of Sendai virus in rat sera. Methods the SeV antigen proteins separated by SDS-PAGE were used in the WB method; 20 sera from germ free rats, 227 sera from SPF rats and 63 sera from clean rats were analyzed by ELISA, IFA，those candidate positive samples were tested by WB. Results The 20 germ free rats were determined SeV negative by all of the 3 methods; all of the SPF rats were determined SeV negative by IFA, but 1.32% of these SPF rats were determined SeV positive by ELISA, and 2/3 of these ELISA determined positive sera were confirmed by WB; The SeV positive rate in clean rats were 18.12% by ELISA, 11.34% by IFA, and 15.87% by WB. Conclusion the detection sensitivity gradient of the 3 methods from high to low is ELISA, WB, and IFA. And WB should be an alternative SeV detection method for those indeterminate samples by IFA and ELISA.