Objective:To establish an atomic absorption spectrophotometry and flame method for the determination of sodium,potassium,magnesium and calcium ions in compound sodium acetate ringer injection.Methods:The A3AFG-12 A3 atomic absorption spectrophotometer,XS205DU and XP6 electronic balances were used.Cesium chloride was used as the ionization inhibitor for the determination of sodium and potassium ions,and lanthanum chloride was used as the ionization inhibitor for the determination of magnesium and calcium ions.The contents of sodium,potassium,magnesium and calcium were determined at 589.3,766.5,285.2 and 422.7 nm,respective-ly,and the methodol was verified.Results:Four ions had good linear relationships in the concentration range of 0.15-1.20,0.2-1.6,0.05-0.4,and 1.014-5.069 μg·mL-1,and the correlation coefficients were r=0.999 6,r=0.999 3,r=0.999 6,r=0.999 0,respectively.The average recoveries were 98.5％,98.1％,93.2％and 95.0％,respectively.The contents of sodium,potassium,magnesium and calcium ions in 5 batches of injection samples were measured in the range of 3.186-3.221,0.155-0.160,0.023-0.026 and 0.056-0.059 mg·mL-1,respectively.Conclusion:The established method has high reproducibility and accuracy,and is suitable for the determination of sodium,potassium,magnesium and calcium in compound sodium acetate ringer injection.