The matrix metalloproteinases(MMPs) are a family of zinc-dependent endopeptidases moleculars which are associated with the breakdown of collagens and other constituents of extracellular matrix.And matrix metalloproteinase-9,also known as gelatinase-B,belongs to the gelatinases of the matrix metalloproteinases family.Its main function is to decompose extracellular matrix,participate in many physiological processes.Recent studies showed that MMP-9 took part in the pathological genesis and development of essential hypertension,including the development of hypertrophy,dysfunction of vessels,and so on.Detecting MMP-9 may be a non-invasive method to predict the genesis,development and prognosis of essential hypertension.Many drugs and MMP-9 inhibitor can regulate the level of MMP-9,thereby influence the development of essential hypertension.