B cell maturation antigen (BCMA) is a receptor of B lymphocyte stimulator (BLyS). Human IgG1Fc fusion proteins with the extracellular domain of BCMA(eBCMA), also called decoy receptors, have beenused as a potential BLyS antagonists to block BLyS activities. In order to design novel BLyS antagonistpeptides, computer-aided homologue modeling was used to construct an eBCMA-Fc fusion protein based on thecrystal structures of BCMA and Fc fragmant. To ensure the activity of eBCMA not to be interfered by Fcfusion, the root mean square distance (RMSD) for eBCMA and Fc were calculated to be 0.036 nm and 0.064nm, respectively, based on molecular docking modeling. An eBCMA-Fc fusion gene was constructed andintroduced into E. coli for expression. As expected, the purified 36 kD eBCMA-Fc fusion protein was able tobind BLyS in vitro at a dosage-dependent manner and demonstrated an anti-proliferative activity induced byBLyS in Daudi cells. The results have provided useful information on the evaluation of computer modeling andthe in vitro biological activity for the design of potential BLyS antagonist peptides.