Perovskite KTa0.35Nb0.65O3 thin films were synthesized from an alkoxy-derived precursor by the chemical solution deposition method. Highly (100) oriented KTa0.35Nb0.65O3 thin films were successfully synthesized on MgO(100) and Pt(100)/MgO(100) substrates. X-ray pole figure measurements showed that KTa0.35Nb0.65O3 films had excellent in-plane and out-of-plane relations to MgO(100) and Pt(100)/MgO(100) surfaces. The KTa0.35Nb0.65O3 film showed the Curie temperature at about 100°C with a diffused transition. Typical polarization-electric field (P–E) hysteresis loops were observed for KTa0.35Nb0.65O3 films on Pt(100)/MgO(100) substrates. The remanent polarization (Pr) of the KTa0.35Nb0.65O3 film gradually decreased with increasing temperature. The pyroelectric coefficient after poling was about 1.2×10-8 C/(cm2K) at room temperature.