The compounds with general formula Bi2SrV2-xThxO9, where (x=0.05, 0.1, 0.2, 0.3, 0.6) were carefully synthesized and processed by using mixed techniques solid state reaction and solution routes with sintering temperature at 880 °C for 20 h. XRD – analysis of the prepared samples proved that thorium(IV)-dopant can substitute successfully until x=0.55 mole on the Bi-layered perovskite crystal structure without damaging the original perovskite structure . It was observed that Th-dopings have slight to moderate effects on both ESR-signals and conduction mechanism of Th-doped Bi-Sr-V-O regime. Electrical measurements indicated that the energy gap Eg and number of electrons in conduction band Ncb increase as the ratio of Th doping increases from x=0.05 till x=0.6 mole respectively due to the increasing of paramagnetic character of thorium than vanadium