Non ⁃puerperal mastitis（NPM）is a rare benign breast disease，which is intractable. Its inci⁃ dence is increasing year by year in recent years. NPM includes mammary duct ectasia（MDE），periductal mastitis （PDM），plasma cell mastitis（PCM）and granulomatous lobular mastitis（GLM）. Clinically，NPM is often misdi⁃ agnosed or treated improperly，leading to bad consequences such as longer course，poor curative effect，obvious breast deformity and more medical expense. In this review，classification，risk factors，diagnosis，treatment and prognosis of NPM are summarized by searching and reading literature about NPM from both domestic and foreign database，in order to provide a basis for clinicians to diagnose and treat NPM and open up a new insight to it as well.