Objective To prepare a high performance electrochemical immunosensor for detecting Brucella abortus(B.abortus).Methods Prussian blue(PB),multi walled carbon nanotubes(MWCNTs)and gold nanoparticles(GNPs)(PB-MWCNTs-GNPs)nanocomposites were prepared,and appropriate antibody was used to construct the immunosensor for detecting B.abortus samples.The optimal conditions were clarified by examining the key factors in sensor construction,and then the performance of the sensor was evaluated.Results The optimal construction conditions were determined as follows:the ratio of MWCNTs-PB was 1∶5,the drying temperature was 37 ℃,the pH value of buffer system was 7.5,and the incubation time of antibody and sample was 1 h and 30 min,respectively.B.abortus exhibited a good linear relationship,when ranging from 10 to 1 × 105 CFU/mL.The sensor had good anti-interference ability,repeatability,stability and high accuracy.Conclusion Our prepared PB-MWCNTs GNPs nanomaterials modified electrochemical immunosensor for detecting B.abortus is easy to prepare,has good performance,and can provide reference for the early clinical diagnosis of brucellosis.