Sulfide solid electrolytes possess high ionic conductivity and moderate dendrite suppression capability, but rather poor compatibility against oxide cathodes and metallic Li. Here, we report O-doped Li6PS5Br as solid electrolyte synthesized by a facile solid-state sintering. Different from other O-incorporated sulfides, the O atoms in Li6PS5-xOxBr prefer to substitute the S atoms at free S2- sites rather than those at the PS4 tetrahedra. Remarkably, without deteriorating the ionic conductivity, this inorganic solid electrolyte with O doping exhibits comprehensively enhanced properties including excellent dendrite suppression capability, superior electro-chemical and chemical stability against Li metal as well as high voltage oxide cathodes, and good air stability. Li (Ni(0,8)Co(0.1)Mno(0.1))O-2 and LiCoO2-based all-solid-state batteries with Li6PS4.7O0.3Br electrolyte deliver high specificcapacity, superior rate capability, and outstanding cycling stability accompanied with low interfacial resistivity. This type of inorganic solid electrolytes is promising for all-solid-state batteries with high energy density.