The ion current density (ICD) of End-Hall ion source at different conditions were determined with a Frady cup. The ZrO_2 films were deposited with different Ar+ ICD. The influence of ICD on refractive index, crystal phases, index inhomogeneity of films was studied. The effect of ICD on refractive index was analysed by a momentum transfer model. According to a thermal-spike theory, it is evidenced that the ICD didn′t influence the crystal structure of the films.