High k dielectric HfO2 films were deposited on p-type Si(100) substrates by e-beam evaporation. The composition of the films is determined to be stoichiometric. The structure changes from almost amorphous to polycrystalline after annealing. The films have very flat surface(rms roughness less than 0.3nm) and no voids appear even after high-temperature annealing, indicating a good thermal stability. The refractive index of HfO2 film is 2.09 (at 600?nm). The dielectric constant is 19. All the characteristics show that e-beam evaporation is a good method to deposit HfO2 thin films as dielectric.