Abstract: To examine and improve the analytical method of ⁹⁰Sr in seawater, we participated in the international comparison of ⁹⁰Sr analysis in seawater organized by International Atomic Energy Agency(IAEA) via the method of solvent extraction with bis-2-ethylthexyl-phosphoric acid(HDEHP) in n-heptane with β counting.The result was consistent with the reference value provided by IAEA.The minimum detection activity is as low as 0.14 Bq/m³ based on the present method.This analytical method of ⁹⁰Sr can be the supplemental method for the national environmental protection standard PRC HJ815-2016 and is one of candidate methods for state standard on ⁹⁰Sr analysis in seawater to satisfy the demand of ⁹⁰Sr analysis in seawater under the background of a rapid development of nuclear power plants along the coastline of China.