The invention relates to a technological method for extracting and separating quadrivalent cerium, thorium, fluorine and less-cerium trivalent rare-earth from rare earth sulfate solution. The rare earth sulfate solution, which is obtained through processing the rare-earth ores and contains high-valence cerium, the fluorine, the thorium and ferrum, is used as raw material; synergistic extraction agent basing on P507 and P204 is adopted for extracting and separating; the cerium (1V), the thorium, the fluorine, and the ferrum are extracted into an organic phase, then selective washing and back extraction are performed step by step to obtain three products that are the cerium, the fluorine, and the thorium, the trivalent rare-earth is left in a water phase, and then unsaponifiable P507 or thesynergistic extraction agent basing on P507 is adopted to perform multistage fractional extraction to separate single rare earth elements. The technological method has the characteristics that the synergistic extraction agent basing on P507 and P204 is adopted, the thorium is easy to perform the back extraction, and extraction capacity is large, and the emulsification is not generated during the extraction process; the cerium (1V), the thorium, the fluorine, the ferrum and the trivalent rare-earth are extracted and separated in the same extraction system; both extraction and the separation adopt unsaponifiable extraction agent, and ammonia-nitrogen wastewater is not generated; in addition, the thorium and the fluorine are recovered as products, and the pollutions caused by thorium-containing waste residue, fluoride-containing wastewater and the ammonia-nitrogen wastewater are eliminated from headstream. Therefore, the technological method has the advantages of simple procedures, greenenvironmental protection, and low manufacturing cost.