More than 92% of rubidium resources on the earth exist in salt lake brine and underground brine. Rubidium in brine coexists with a large amount of potassium with very similar physical and chemical properties, making the extraction technology of rubidium extremely difficult, and a large amount of rubidium resources in brine have not been rationally utilized. Therefore, the development of a new type of high-selectivity rubidium-potassium separation extractant is of great significance to the establishment of efficient separation and extraction technology of rubidium. By modifying the structure of 4-tert-butyl-2-(α-methylbenzyl)phenol, the traditional rubidium extractant, the steric hindrance effect of tert-butyl is reduced and the reaction efficiency of rubidium and extractant is improved. A new extractant 4-ethyl-2-(α-methylbenzyl)phenol was obtained. The thesis carried out the research on the extraction and separation performance of potassium rubidium 4-ethyl-2-(α-methylbenzyl)phenol. The results show that the new extraction agent 4-ethyl-2-(α-methylbenzyl)phenol and potassium rubidium brine are extracted and separated with a ratio of 10:1. The minimum separation coefficient of rubidium potassium can reach 15 or more, showing excellent separation performance ; When the organic phase is composed of 0.8mol/L extractant and D60 solvent oil, the alkalinity of the aqueous phase is 0.5mol/L sodium hydroxide, and the extraction time is 3 minutes, the single-stage extraction rate of rubidium can reach more than 76.0%, rubidium potassium The separation coefficient can reach more than 26. After repeated use, the extraction rate of rubidium can be maintained above 73% and the separation coefficient of rubidium potassium can reach 23, without a significant drop. It provides a new way and idea for the extraction and separation technology of rubidium in high potassium brine.