Abstract: With the increasing demand for high performance secondary battery energy density and safety performance, the development of new type of solid-state battery is a hot spot in the field of energy researches. The key part of solid-state batteries is the solid electrolyte, and the anti-perovskite type electrolyte Li₃OCl has attracted extensive attentions due to its wide voltage window and high ionic conductivity. In general, doping modification can further improve the ionic conductivity of Li₃OCl and stabilize its cubic phase structure. However, researches on lanthanum doping using rare earth elements are still lacking. China is rich in rare-earth reserves, so it is of great value to systematically study the application of rare earth elements in Li₃OCl based batteries. Herein, the effect of lanthanum doping by Nd element on ionic conductivity of Li₃OCl electrolyte was investigated. By precisely regulating the doping amount, the ionic conductivity of Li₃OCl can be successfully increased from 5.2×10^-4 S/cm to 8.3×10^-4 S/cm. The solid-state battery realized a stable cycling at the rate as high as 3C. The doping research of Nd in Li₃OCl can provide effective theoretical guidance for the development of high-power solid-state battery and the application on new energy vehicles.