Abstract: Alkaline phosphatase(AP) is a kind of hydrolase，which catalyzes the nonspecific hydrolysis of phosphate monoester to produce phosphate or transfer phosphate．AP exists widely in microbial and animal kingdom．AP plays a vital important role in phosphate cycle of world creatures，and has been used widely in the fields of diagnostics，biochemistry and molecular biology．In this paper，the history，the reaction mechanism and application of alkaline phosphatase was reviewed．

Key words: alkaline phosphatase; nonspecific phosphomonoesterase; reaction mechanism