The invention belongs to the technical field of a battery, and relates to a battery cover plate and a processing method thereof. The battery cover plate comprises a substrate, a positive pole post, a negative pole post, a positive sealing assembly and a negative sealing assembly, wherein a positive pole post hole and a negative pole post hole are formed in the substrate, the positive pole post is arranged in the positive pole post hole, the negative pole post is arranged in the negative pole post hole, a first annular boss is arranged at an outer circle of an upper part of the positive pole post, a second annular boss is arranged at an outer circle of an upper part of the negative pole post, a first fixed block is arranged at a middle part of the positive pole post, a second fixed block is arranged at a middle part of the negative pole post, the positive sealing assembly is arranged between the substrate and the positive pole post, the negative sealing assembly is arranged between the substrate and the negative pole post, the positive sealing assembly comprises a first positive sealing piece and a second positive sealing piece, and the negative sealing assembly comprises a first negative sealing piece and a second negative sealing piece. The battery cover plate is stable in sealing performance and simple in structure, and is difficult to corrode and easy to process.