Abstract: ⁹⁰Sr(T_1/2=28.9 a) is a highly toxic nuclide with high heat release and strong exothermic properties, and the content of ⁹⁰Sr in radioactive waste must be accurately measured before disposal. The separation of ⁹⁰Sr from radioactive waste is the key to accurate measurement. By changing the synthesis reaction path and optimizing the synthesis reaction parameters, this work solves the problems of hydrogenation hazard and purification difficulties in the synthesis reaction of di-tert-butyldicycloh-exyl-18-crown-6(DtBuCH18C6), and achieves the synthesis of high purity products. Using DtBuCH18C6 as the extraction agent, the solvent extraction method was used to study the effects of diluent type, extractant concentration, nitric acid concentration and organic to aqueous phase ratio on the strontium extraction performance, so as to determine the optimal extraction conditions for the selective separation of Sr²⁺, and establish an effective and rapid separation method for Sr²⁺, which laid a foundation for the future extraction of ⁹⁰Sr from the high-level waste liquid.