La2Sn2O7/SnO2 composite powder was firstly synthesized by a low-cost co-precipitation, and Ag-La2Sn2O7/SnO2 electrical contact material was prepared by powder metallurgy method. Anti-arc erosion properties, mass loss and Vickers hardness of Ag-La2Sn2O7/SnO2 were investigated, and anti-arc erosion mechanism was discussed. Results show that the welding force of Ag-La2Sn2O7/SnO2 composite is much better than that of Ag-SnO2, which is because the new phase La2Sn2O7 can increase the viscosity of melt poor and improve wettability between silver and tin oxide to some extent. Meanwhile, Flatter arcing area and “beads-like” particles embedded scatteredly in the surface could decentralized arc energy by “Pinning Effect”, which can decrease temperature rise and lower welding force. Ag-La2Sn2O7/SnO2 composite could be a leading candidate material for electrical contacts in the future.