Abstract: The electrical and processing properties of AgSnO₂ composite contact materials were improved by doping. Based on the first principles of density functional theory, the elastic constants of SnO₂ supercells doped with Cr-Y and Cr-Ce were calculated by simulation, and the rare earth element Y with better mechanical properties was selected for simulation and experiment of electrical properties. The effects of Cr and Y doping on the electrical properties of SnO₂ were analyzed from the energy band structure and density of states. The results show that the band gap of SnO₂ decreases and the energy required for electron transition cuts down after doping. The doped SnO₂ powder was prepared by sol-gel method, and its phase structure was analyzed by XRD. It is verified that doping ions enter into the SnO₂ lattice to form solid solution, and achieves the alternative doping model established by simulation. The doped AgSnO₂ composite contact materials were prepared by powder metallurgy method, and their densities, hardnesses and conductivities were measured. The conductivities of doped AgSnO₂ contact materials are improved, and Cr-Y co-doped is the best among them, which verifies the simulation results. JF04D type electrical contact material test system was used to test the electrical contact performance of contact materials. The test results show that doping Cr and Y can effectively reduce the arc energy of AgSnO₂ contact materials, improve the arc erosion resistance, inhibit the arc ablation of contact materials, and stabilize the arc erosion resistance and welding resistance of contact materials.