Agriculture: phosphoric acid is an important fertilizer (superphosphate, potassium dihydrogen phosphate, etc.) of raw materials, but also the raw material feed nutrients (calcium dihydrogen phosphate) is.
Industrial: Phosphoric acid is an important chemical raw material, the main role is as follows:

Treating the metal surface, the metal film formed on the surface of insoluble phosphate to protect the metal from corrosion.
A mixture of nitric acid and chemical polishing agent to improve the surface finish of the metal.
Production of detergents, pesticides, raw phosphate.
Production of phosphorus-containing flame retardant materials.

Food: Phosphoric acid is one of food additives in food as sour agents, yeast nutrients, in respect of Coca-Cola contains phosphoric acid. Phosphate is also important food additives, enhancers can be used as nutrients.
Medicine: phosphate phosphorus can be used for making drugs, such as glycerol phosphate.