Multiferroic material is one of hot spots in the materials research area which can be widely used in many new functional devices. Barium titanate (BaTiO₃, BTO) has attracted many interests for its multiferroic properties, such as ferroelectricity, high dielectric constant and electro-optical properties at room temperature. The BaTi_0.94(TM_1/2Nb_1/2)_0.06O₃ (TM=Mn/Ni/Co) ceramic samples were prepared by solid state reaction method, and their structure, electrical, magnetic, and optical properties were systematically studied. The crystal structure of all doped samples changes from tetragonal to cubic phase without any hexagonal phase depending on ionic radius. Weakening of Raman scattering peaks of BTO tetragonal phase further proves the phase transition to cubic phase caused by doping. The Curie temperature (T_C) has a dramatic decrease with the dopant as the phase transition from tetragonal phase to cubic phase. Although the ferroelectricity is weakened, it is still existed. The magnetic measurement suggests that Ni-Nb doped sample has the strongest ferromagnetism among different dopants which can be deduced by the F-center exchange (FCE) theory. Furthermore, energy gaps of BaTi_0.94(TM_1/2Nb_1/2)_0.06O₃ are obviously reduced compared to that of BTO, which can be reasonably explained by impurity level and band theory. These results indicate that BTO based multiferroic ceramics with ferroelectric and ferromagnetic coexisting at room temperature can be obtained by B-site co-doping, which can be expected to be widely used in multiferroic functional devices.