Objective：To investigate the serum amyloid A（SAA） protein levels possibly associated with the common cardiac and cerebral complications in patients with obstructive sleep apnea syndrome（OSAS）. Methods：Based on apnea hypopnea index（AHI） measured by polysomnography，62 patients with OSAS only were divided into mild OSAS group（n = 16），moderate OSAS group（n = 18） and severe OSAS group（n = 18）. Eighteen healthy subjects with matched age and BMI were recruited as control group. SAA specific monoclonal ELISA method was used to measure and compared morning SAA concentrations among different groups. In addition，correlation of SAA with AHI and minimal pulse oxygen saturation（miniSpO2） was analyzed in OSAS patients. Results：Analyzing on SAA concentrations demonstrated that compared with control group（9.19 ± 3.87 μg／ml）, SAA levels were significantly higher in mild OSAS group（13.49 ± 3.08 μg／ml，P < 0.05），in moderate OSAS group（18.73 ± 5.29 μg／ml, P < 0.01），and in severe OSAS group（38.56 ± 10.11 μg／ml，P < 0.01）. There was a significant difference in SAA levels among different groups. As the degrees of OSAS become more severe，SAA level became higher. Analysis indicated that SAA was positively correlated with AHI（r = 0.796，P < 0.001），but negatively correlated with miniSpO2（r = -0.631，P < 0.001）. Conclusion：SAA levels were significantly higher in OSAS patients and such an elevation turned to be more remarkable as degrees of OSAS become more severe. Elevated SAA level may contribute to some increased risk for cardiovascular and neuronal dysfunction in OSAS patients.