Objective：To investigate the association between obstructive sleep apnea hypopnea syndrome（OSAHS） and metabolic syndrome（MS） in male Chinese patients. Methods：There were 86 male patients with OSAHS recruited as OSAHS group, which was further divided into mild, moderate and severe OSAHS subgroups. 241 normal male adults（AHI<5） with their age and body weight index （BMI） matched were recruited as control group. The incidence of MS were compared between normal and OSAHS subjects. All subjects investigated were tested for their metabolic parameters of peripheral circulation. In OSAHS subgroup continuous positive airway pressure（CPAP） treatment was performed in 25 subjects（treatment group）. Comparison was made for correlation and difference of all parameters between OSAHS and control groups as well as before and after CPAP treatment in treatment group. Results：There was a significant difference between two groups in the following parameters：diastolic and mean arterial blood pressure, circumference of waist（WC） and hip（HC）, waist-to hip ratio（WHR） and high density lipoprotein cholesterone（HDL-C）. Compared with control group, the incidences of MS were not only significantly higher in OSAHS group as well as in its subgroups, but also became more remarkably high as OSAHS became more severe. Multiple factor stepwise regression analysis showed that OSAHS was the independent risk factor of MS. After CPAP treatment, there was a significant decrease in WC, systolic and diastolic blood pressure, FBG, IR and incidence of MS. Conclusion：OSAHS is closely associated with MS in male patients. OSAHS is one of the independent risk factors. CPAP treatment can improve IR and reduce the incidence of MS.