In this paper, Lead-free based on 0.97(${\text{K}}_{0.48}$${\text{Na}}_{0.48}$${\text{Li}}_{0.04}$)(${\text{Nb}}_{0.8}$${\text{Ta}}_{0.2}$)O₃–0.03${\text{Bi}}_{0.5}$${\text{Na}}_{0.5}$TiO₃ with additives La₂O₃ (1, 2, 3, 4 wt.%) was prepared by the solid reaction method, and the effect of La dopant on the structural and electrical properties is investigated. The result indicates La dopant considerably decreases the optical band gap compared to the undoped composition. On the other hand, La doping leads to the higher dielectric property in a wider temperature, providing possibilities and directions for the subsequent development of ferroelectric photovoltaic materials with electrical properties and low optical band gap in a dramatical manner.