High refractive index glasses with nominal composition of 0.35La(2)O(3)-(0.65-x)Nb2O5-xTa(2)O(5) (x0.35) were prepared by aerodynamic levitation method. The effect of Ta2O5 substituting on their thermal and optical properties was investigated. All the glasses obtained were colorless and transparent. Differential thermal analyzer results show that as the content of Ta2O5 increased, the thermal stability of the glasses increased but the glass-forming ability decreased. The transmittance spectra of all the obtained glasses exhibited a wide transmittance window ranging from 380 to 5500nm. As the content of Ta2O5 increased, the refractive index of the glasses was enhanced from 2.15 to 2.21 and the dispersion was reduced with the Abbe number increasing from 20 to 27.