The invention relates to a separation and recovery method for radioactive waste slag and specifically relates to a separation and recovery method for monazite slag. The separation and recovery method comprises the following steps: acid leaching, pressure filtration, water washing, extraction of valuable components and treatment of filtration slag. The separation and recovery method provided by the invention performs low-acid and low-temperature leaching on monazite slag, so that a liquid phase and a solid phase are easy to separate; after an ore dressing process is adopted for performing ore dressing and alkali decomposition on secondary slag, closed-loop circulation and recovery of uranium, thorium and rare earth is realized; and simultaneously, extraction raffinate waste acid is recycled, so that the emission of waste water is reduced, the consumption of sulfuric acid and fresh water and the treatment cost of the waste water are reduced, the production cost is reduced, the recovery rate of the valuable elements, namely the uranium, the thorium and the rare earth is more than 97%, and the whole process has no emission of the radioactive waste water and waste slag.