Abstract: Phosphate ore is an important raw material for phosphorus chemical production and plays an important role in the development of national economy. The negative factors such as the decrease of phosphate ore inclusion grade, the similarity of mineral properties between useful minerals and gangue minerals, and the excessively fine mineral mosaics affect the development of phosphate ore dressing technology. The study of the interaction mechanism between agents and minerals is helpful to improve the mineral separation effect, the importance and flotation status of phosphate ores were reviewed, and the application and mechanism of sodium hexametaphosphate in flotation of medium-grade and low-grade phosphate ores were emphatically studied. It is found that sodium hexametaphosphate has two main roles in phosphate ore flotation: First, the addition of sodium hexametaphosphate will form a competitive adsorption with the collector on the apatite mineral surface, which further inhibits the adsorption of the collector on the apatite mineral surface, thus changing the hydrophilicity of the mineral; The second is that the addition of sodium hexametaphosphate will cause the change of mineral surface potential, so that the interaction force between mineral particles will change accordingly, increasing the dispersion of mineral particles, and thus optimizing the mineral flotation conditions.