Sr/Ca and Mg/Ca ratios of ostracod shells in lacustrine sediments can be used to reconstruct the palaeotemperature and palaeosalinity of lakes.According to the characteristics of the double channel sequential scan inductively coupled plasma atomic emission spectrometry (ICP-AES), the most sensitive emission lines and optimum channels are chosen to determine trace Sr and Mg of gamma grade ostracod shells sample,while all determined conditions are optimized.The detection limits of Sr and Mg are 1.lμg/L and 1.4/μg/L respectively.In this paper,Sr/Ca and Mg/Ca ratios are accurately determined, and the recovery test is satisfactory.