Abstract: In order to identify the linear B-cell epitope of structural protein BP26 of Brucella abortus, the BP26 protein was dissected into three overlapping fragments，and expressed in Escherichia coli, respectively. Western blot analysis of the three fused proteins was carried out with sera from Brucella infected cattle. The results showed that the linear B-cell epitope of BP26 protein was located in the 51-165 aa. Based on these, the short peptide protein BP26 2 was dissected into five overlapping fragments further. Finally, we identified that the linear B cell epitope on BP26 is located in the 109-141 amino acid. It was concluded that the MAbs against the protein BP26 could be useful tools for further studying on the structure and function of BP26, as well as for development of diagnostic methods.