The paper investigates the effect of co-doping Tb3+ as an energy-transfer sensitizer on optical properties of YAG:Re3+ (where, Re = Ce, Eu) phosphor films synthesized by sol-gel route. The results suggest that, Tb3+ is a promising sensitizer for improving the optical performances of the as-prepared YAG:Re3+ films, and a Tb3+ co-doping concentration of 20% was found to be an optimum level on account of Tb3+ concentration quenching. Due to the energy-transfer processes of Tb3+Re3+, the as-prepared Y-0.8 Tb(0.2)AG:Re3+ films displayed strong abilities of absorption in the ultraviolet (UV) light range, and bright green-yellow emission for YAG:Ce3+ or red emission for YAG:Eu3+ under 275 nm irradiation, which could be utilized for UV-excited WLED and display applications.