Abstract: Efficiency calibrations and quenching calibrations of ⁹⁰Sr and ⁹⁰Y separated from Sr-Spec resin by liquid scintillation spectrometry were investigated. The chemical recovery of ⁹⁰Y for efficiency calibration was determined. The quenching calibration method and the effects of efficiency calibration, such as liquid scintillation cocktails, addition of carrier, drying, storage time, chemical quenching were studied. The results show that GoldStar LT² is suitable for determinations of ⁹⁰Sr and ⁹⁰Y. Whether drying of ⁹⁰Sr calibration source or not and yttrium carrier addition of ⁹⁰Y calibration source or not, there is no effect on the Cerenkov efficiency calibration. The efficiency calibration of ⁹⁰Y should be completed within 10 h after the separation of ⁹⁰Sr and ⁹⁰Y. ⁹⁰Sr source should be dried before measurement, and its efficiency calibration should be completed within 10 h. When the preparation method of sample is as same as efficiency calibration source, and the SQP(E) value of sample deviates from that of the standard sample within the range of 8.9%, relative measurement method can be used directly.