Tantalum oxide films have been deposited by 355 nm pulsed laser ablation of metallic Ta target in O-3/O-2 ambient. The structure and the composition of as-deposited and annealed films were examined by X-ray diffraction and Fourier transform infrared spectroscopy. The measurements of the current-voltage and capacitance-voltage characteristics of the Al/Ta2O5/Si capacitors Were performed to reveal the electrical properties of the Ta2O5 films. The effects of annealing temperature on the characteristics of thin films have been studied, The results suggest that the films annealed above 700 degrees C have the structure of orthorhombic beta-Ta2O5, the annealing treatment at high temperature decreases the bulk trap charge, the border trap, and the interface trap densities of as-deposited films, and improves significantly the dielectric and electrical properties of Ta2O5 film.