Geometric structure of W_mB_n(m+n≤7) clusters are optimized by using density functional theory at B3LYP/LANL2DZ level. For ground state configurations, average binding energies, second order differential energies, energy gaps and WIB bond orders are analyzed. It shows that ground state structures of WB_n clusters are flat structures; as m≥2 and m+n≥4, all clusters are cube structure except W₃B cluster. Stability of clusters is getting better and better as W atoms increase. The bonding strength of W-W is significantly higher than those of W-B and B-B key. W atom plays a leading role in stability of clusters. Stability of W₂B₂ and W₃B cluster is the best.