Abstract: In order to detect the risk factors of breast Cancerin Xining city.A hopital-based matched case-control study with 110 case and 110 controls has been condutctedfrom Oct.1996 to Oct.,1998 in Xining city.The subjects were questioned abouttheir reproductive history,history of benign breast diseased,menstrual history, fabily history of cancer,character,psychological injury,occupational stress,history of exposure of breast to X-raybefore 18 year old,past dietary habits and other factors.The conditional Logistic regession method was used for multivariate analysis.Theresults shored that late age at menopuse(p=0.036),less parity(p=0.040),character(depression,loneliness,anxiety,anguish)(p=0.002),high in take of fat(p=0.005),low intake of vegetables(p=0.002)and bean products(p=0.016),menstr ual diso rder(p=0.061),high weght-height ratio(p=0.068)were risk factors for women breast cancer.