The invention relates to a cattle and sheep brucellosis indirect enzyme-linked immunosorbent assay antibody detection kit and a preparation method thereof, belongs to the field of detection of pathogens of zoonotic infections and aims at solving the problems of low sensitivity, poor specificity and the like in detection of Brucella by adopting other antigens. The kit is assembled by taking a recombinant Brucella BCSP31 protein with expression induced by SUMO as an expression vector in Escherichia coli to serve as an antigen-coated ELISA (enzyme-linked immunosorbent assay) plate, adding serum to be detected and rabbit anti-bovine HRP-IgG or rabbit anti-goat HRP-IgG and adding a washing buffer solution, a blocking solution, a TMB (3,3',5,5'-Tetramethylbenzidine) primer solution and a stop solution for matching. The prokaryotic expression vector, namely the SUMO, is utilized to express the Brucella BCSP31 protein in an efficient and soluble manner, the kit is used for establishing a Brucella ELISA detection method, the detection has better repeatability and specificity, and cattle and sheep Brucella can be fast and efficiently detected by utilizing the method.