The invention provides a treatment device for strong brine. The treatment device comprises a hardness removal unit, a decarbonization and denitrification unit, a desilication unit and a softening unit; the hardness removal unit communicates with strong brine source equipment and is used for reducing the hardness of strong brine; the decarbonization and denitrification unit communicates with the hardness removal unit and is used for reducing the ammonia nitrogen content and COD of the strong brine treated by the hardness removal unit; the desilication unit communicates with the decarbonizationand denitrification unit and is used for reducing the silicon content of the strong brine treated by the decarbonization and denitrification unit; and the softening unit communicates with the desilication unit and is used for reducing the hardness of the strong brine treated by the desilication unit. By using the device, the hardness, ammonia nitrogen, silicon dioxide and COD in water can be effectively removed, the strong brine can be efficiently purified, the subsequent treatment unit cannot be polluted by effluent from the treatment device, and the subsequent treatment unit cannot generatea scale formation problem.