Structural and electronic properties of the cubic perovskites BaMO3 (M=Pr, Th and U) are theoretically investigated by using the full potential linearized augmented plane wave (FP-LAPW) method. The exchange correlation of GGA+U is employed in the present DFT calculations to treat the f electrons properly. The structural parameters of the compounds are also evaluated by analytical techniques. The calculated structural parameters by both techniques are found in agreement with the experimental results. Furthermore, the calculated tolerance factors confirm the experimentally observed cubic structure for all the three compounds. The evaluated critical radii of the compounds provide information about the oxygen migration energy and ion conductivity and they also reveals that BaPrO3 posses the highest migration energy. The spin-polarized band structures show that BaPrO3 is a wide band gap semiconductor, BaUO3 is half-metal and BaThO3 is insulator. The magnetic studies of these compounds reveals that BaPrO3 is anti-ferromagnetic, BaThO3 is nonmagnetic/paramagnetic and BaUO3 is ferromagnetic material.