Abstarct: In this thesis, cobalt bismuth oxide BiCoO3 was first prepared by hydrothermal method and anealeed at different temperature. Then structural properties, morphology, optical properties, electrical properties, and magnetic properties as well as dielectric properties of the samples were investigated. X-ray diffraction patterns of the samples confirmed the formation of a cubic bismuth oxide bismuth cobalt phase at the 700℃ annealed sample. The FESEM images of the samples showed that change in annealing temperature causes change in the particles shape and size. Examining the optical properties of the samples indicated that their band gap varies within the range of 1.88-1.75 eV. The Hall effect measurements at room temperature showed that the prepared samples are p-type semiconductor. The magnetic hysteresis loops recorded for samples showed a mixture of weak ferromagnetic and paramagnetism behavior. Also, investigation of dielectric properties of the samples showed that the dielectric constant decreases with increasing frequency.