The incidence of non-puerperal mastitis（NPM）has been increased in recent years，mainly in young women. Individual reports have been reported in men. NPM was mainly divided into three categories：mammary duct ectasia（MDE），periductal mastitis（PDM），and granulomatous lobular mastitis（GLM）. Among them，PDM and GLM were the most common types. In view of the difficulty in the diagnosis and treatment of NPM，which was often confused with inflammatory breast cancer，recurrent attacks after treatment were the characteristics of the disease，resulting its refractory treatment. Moreover，some patients even underwent mastectomy because of this disease，and suffered physiological and psychological trauma. In this paper，we shall review the clinical classification，diagnosis and treatment of NPM combined with existing reports.