Double perovskite Bi2NiMnO6 (BNMO) thin films with and without SrTiO3 (STO) buffer layer have been prepared on Pt (111)/Ti/SiO2/Si(100) substrates by a chemical solution deposition method. The microscopic surface morphology, ferroelectric, and leakage current have been investigated. It is shown that the STO buffer layer can improve the remnant polarization slightly, and reduce the coercive electric field from100 to 36 kV/cm. When the positive voltage was applied on top Au electrode of the BNMO/STO/Pt thin film capacitors, the leakage current was controlled by ohmic conduction. When the negative voltage was applied on bottom Pt electron, the leakage current of BNMO/STO thin film was limited by the traps and the density of carriers at high electric field