In this study, Sr0.6Ba0.4Nb2O6 (SBN) thin films were prepared by radio-frequency (RF) magnetron sputtering. After finding the optimal deposition parameters, the deposited SBN thin films were annealed in a conventional furnace. In comparisons of XRD patterns, the annealing process had improved the crystallization and also had large effects on the crystalline orientation of SBN thin films. As the annealing temperature was risen from 600 to 700 C, the diffraction intensities of (410) and (001) peaks really increased. Annealed at 800 C, SBN thin films showed a highly c-axis crystalline orientation in (001) peak. Effects of annealing temperature on the electrical characteristics were recorded and analyzed, including the polarization-applied electric field curves, the capacitance-voltage curves, and the leakage current density-electric field curves. As the annealing process was used to treat on the as-deposited SBN thin films, the Pr, Ps, and Ec values were really improved. The theorems to cause the drastic variations in the capacitances, the memory windows, and the flat-band shift voltages of SBN thin films were also discussed.