A mixed extractant composed of P204 and Cyanex272 was used to extract Co,Mn and Fe in laterite nickel leaching solution. The optimal extraction agent ratio, pH value of aqueous phase, extraction equilibration time, extraction temperature, and the most suitable acid concentration for back extraction were studied systematically. The results show that the optimum synergistic extraction is obtained under the conditions: the volume ratio of P204 : Cyanex272 : TBP : sulfonated kerosene is 5 : 15 : 5 : 75, pH value of the solution to be treated is 4. 5, the extraction temperature is 60 °C, and extraction time is 8 min. In the process of stripping, Co can be stripped effectively by sulfuric acid at a concentration o£ 50 g/L,Mn can be stripped effectively by sulfuric acid at a concentration of 110 g/L,and Fe can be stripped effectively by HC1 at a concentration of 7 mol/L.