(1) safe and nontoxic properties. As the basic raw material for preparation of sodium citrate from the food, which is absolutely safe and reliable, will not cause harm to human health. The United Nations Food and Agriculture and the World Health Organization for its daily intake without any limits, that the product is a drug-free. (2) biodegradable. Sodium citrate diluted by the large amount of water in nature, some into citric acid, the two coexist in the same system. Citric acid in water by oxygen, heat, light, and the role of micro-organisms, easily biodegradable. The decomposition approach is generally through aconitic acid, itaconic acid, lemon acid, Yu Kang, into carbon dioxide and water. (3) complexing ability with metal ions. Sodium citrate on Ca2 +, Mg2 + and other metal ions with good complexing ability of the other metal ions such as Fe2 + and other ions are also good complexing ability. (4) excellent solubility in water, and the solubility increases with rising water temperatures. (5) has a good pH control and buffer performance. Sodium citrate is a weak acid alkali salt, and citric acid can form a strong compatibility of the pH buffer, so in some appropriate changes in a wide range of pH has an important use of the occasion. In addition, sodium citrate also has excellent performance and stability retardation