Objective To investigate the implication of oxidation protein product ( advanced oxidation protein product, AOPP) , an index of oxidative stress in obstructive sleep apnea-hypopnea syndrome ( OSAHS) . Methods 47 patients with OSAHS and 48 normal controls were enrolled. The concentration of AOPP was measured by spextrophotometry after ameliorated, while superoxide ( SOD) , malonaldehyde ( MDA) , glutathione peroxidase ( GSH-PX) in morning blood samples were detected by Xanthine oxidase test. Results ( 1) Plasma AOPP and MDA were significantly elevated in OSAHS compared with those in control group ( both P lt;0. 01) . Plasma SOD and GSH-PX were significantly lower in OSAHS compared with those in control group ( both P lt;0. 01) . There were significant differences in the plasma AOPP, MDA, SODand GSH-PX among different severity of OSAHS ( all P lt; 0. 01) . Plasma AOPP and MDA were increased and SOD and GSH-PX were gradually decreased with the progression of OSAHS. ( 2) Plasma AOPP correlated well with MDA, SOD and GSH-PX, moreover, AOPP was positively correlated with apnea hyponea index or lowest oxygen saturation. Conclusion AOPP is an alternative index reflecting both oxidative streess and tissue injury in patients with OSAHS.