Calcium is one of the important nutrients in milk.It plays a crucial role in the human health.The ratio of calcium and phosphorus in milk is associated.Therefore,it is very important to be able to accurately analyze the calcium in milk.There are many methods to detect calcium content in milk.But on the basis of the milk's fluid and the calcium's specificity,complex titration with EDTA was the best detection method.The digestion method,the standard solution preparation,the indicator dosage,the amount of NaOH,time,temperature were discussed.Then the modified method for calcium determination by EDTA titration is proposed.Milk was digested by 5∶1 HNO3-HClO4 at 260℃ for 4h.This method saved the reagents and digesting time,the recovery was also high.The best detecting condition was at pH 12.0 with 0.5% liquid indicator.