A double-sided tunneling silicon-oxide passivated back-contact solar cell, comprising a silicon wafer with a front surface and a back surface, wherein on the back surface of the silicon wafer, a first semiconductor layer and a second semiconductor layer are provided, and on the front surface of the silicon wafer, a passivation layer is provided, wherein the first semiconductor layer comprises a first tunneling silicon-oxide layer and a first doped polycrystalline silicon layer, sequentially arranged from inside to outside; the passivation layer comprises a second tunneling silicon-oxide layer and a second doped polycrystalline silicon layer, sequentially arranged from inside to outside; a thickness of the first doped polycrystalline silicon layer is 3-8 times that of the second doped polycrystalline silicon layer; the back surface of the silicon wafer is provided with a first phosphorus-doped diffusion region, and the front surface of the silicon wafer, which is a textured surface, is provided with a second phosphorus-doped diffusion region; and a ratio of a depth of the first phosphorus-doped diffusion region to a depth of the second phosphorus-doped diffusion region ranges from 1-6: 1; and the first tunneling silicon-oxide layer, the first doped polycrystalline silicon layer, the second tunneling silicon-oxide layer, and the second doped polycrystalline silicon layer are formed by following method: forming a corresponding tunneling silicon-oxide layer and doped polycrystalline silicon layer on both the back surface and the front surface of the silicon wafer are formed simultaneously; and the tunneling silicon-oxide layer and the doped polycrystalline silicon layer are formed sequentially comprises: at first, simultaneously depositing undoped intrinsic amorphous silicon layers on surfaces of corresponding tunneling silicon-oxide layers on the back surface and the front surface; then, plating a phosphorus-doped film layer by in-situ doping on the back surface, wherein the phosphorus-doped film layer is either a polycrystalline silicon film layer or an amorphous silicon film layer, and a sum of thicknesses of the intrinsic amorphous silicon layer and the phosphorus-doped film layer is controlled to be 3-8 times a thickness of the intrinsic amorphous silicon layer; proceeding with phosphorus diffusion, ensuring that both the front surface and the back surface of the silicon wafer remain exposed during the phosphorus diffusion to ensure simultaneous phosphorus diffusion and simultaneous formation of phosphosilicate glass layers on the front surface and the back surface; and finally, removing phosphosilicate glass layers. at first, simultaneously depositing undoped intrinsic amorphous silicon layers on surfaces of corresponding tunneling silicon-oxide layers on the back surface and the front surface; then, plating a phosphorus-doped film layer by in-situ doping on the back surface, wherein the phosphorus-doped film layer is either a polycrystalline silicon film layer or an amorphous silicon film layer, and a sum of thicknesses of the intrinsic amorphous silicon layer and the phosphorus-doped film layer is controlled to be 3-8 times a thickness of the intrinsic amorphous silicon layer; proceeding with phosphorus diffusion, ensuring that both the front surface and the back surface of the silicon wafer remain exposed during the phosphorus diffusion to ensure simultaneous phosphorus diffusion and simultaneous formation of phosphosilicate glass layers on the front surface and the back surface; and finally, removing phosphosilicate glass layers.