Abstract: Objective T o explore the causal association between prostate cancer and smoking,drinking and physical activity among Cantonese.Methods A hospital-based case-contr ol study was conducted from 2005 throug h 2006 in four affiliated hospitals of Sun Ya-tsen University at Guang zhou.The cases and controls were matched by age(±5years),male,race of Han and the same resident location.All the subjects were interviewed in the hospitals by experienced investigators face to face.T he data were analyzed with Conditional Logistic Regression Model.Results When BPH was referred to,men who smoked 20 cigarettes per day or more were in nearly two-fold risk as nonsmoker(OR=2.19,95%CI 0.87~5.52).Men with over 40 pack-y ears of smoking(OR=2.08,95%CI 0.81~12.679)tended to increase the risk of developing prostate cancer.When other diseases referred,an elevated risk was found for those men who had an amount of alcohol consumption over 100 g per day compared with non-drinkers(OR=2117,95%CI 0.7~6.63).A drinking duration of more than 40 years added a man's risk of developing prostate cancer(OR=3.35,95%CI 0.89~5.30).Conclusion Heavy smoking,long drinking duration and less physical activities may increase the risk of prostate cancer.