Abstract: There is a large disparity among the contents of Mg,Ca,Zn and Al in tetraatomic hydrotalcite-like heat stabilizer.Determination method of their contents was discussed.An analyte solution was first treated with an excess of NH4F,which masked Al<SUP>3+</SUP>,Mg<SUP>2+</SUP>,and Ca<SUP>2+</SUP>,thereby leaving only Zn<SUP>2+</SUP>was titrated with standard EDTA.Another analyte was buffered to a pH of 3.5,treated with excess EDTA and boiled,adjusted to pH=4.2 to ensure complete complexation of Al<SUP>3+</SUP>and Zn<SUP>2+</SUP> with EDTA.Surplus EDTA was titrated with standard Cu<SUP>2+</SUP>solution.Then,Al<SUP>3+</SUP> was determined by displacement titration.Using little volume precipitation method,CaCO<SUB>3</SUB> and Mg(OH)<SUB>2</SUB> precipitates were separated from water-soluble ZnO<SUP>2-</SUP><SUB>2</SUB> and AlO<SUP>2-</SUP>.Afterwards to dissolve CaCO<SUB>3 </SUB>and Mg(OH)<SUB>2</SUB> in HCl solution,total content of Ca<SUP>2+</SUP> and Mg<SUP>2+</SUP>was titrated with standard EDTA.In order to mask Ca<SUP>2+</SUP> with EGTA,Ba-EDTA-Na<SUB>2</SUB>SO<SUB>4</SUB> solution was added into Ca-Mg solution and Mg<SUP>2+</SUP> was titrated with standard EDTA,content of Ca<SUP>2+</SUP>&nbsp; could be obtained by subtraction.The method is accurate and precise and can meet the requirements of industry analysis.