Abstract: Na-As doped LiFePO4 has been investigated by using first-principle calculations based on density functional theory. The electronic structures of Na-As doped material are calculated, the results show that Na-As doping in small quantity could not change the inherent attribute of LiFePO4, but it was an effective way to modify material performance. The doped material has the narrow band gap and low Li-intercalation potential and the doping Na- As ions could not block the diffusion path of lithium ion.