Objective:To investigate serum PCSK9 and LDL-C level changes in obstructive sleep apnea-hypopnea syndrome(OSAHS),and assess the prediction for OSAHS combined with cerebral infarction. Methods:87 patients were admitted to this trial in our hospital,and they were divided into three groups:OSAHS combined with cerebral infarction group (group A),isolated OSAHS group(group B) and control group(group C). Serum PCSK9 concentration was measured by ELISA and LDL-C level were measured by automatic biochemical analyzer,and then they were applied SNK test to perform statistical analysis. Polysomnography(PSG) results of group A and group B were also compared. Furthermore,correlational analyses were conducted between the two factors and PSG results in OSAHS associate with cerebral infarction and isolated OSAHS patients respectively. Results:①Serum PCSK9 and LDL-C levels were higher in group A than those in group B and group C (P < 0.05). ②PSG results showed that patients in group A were more severe than that in group B (P < 0.05). ③Serum PCSK9 and LDL-C levels in OSAHS associate with cerebral infarction and isolated OSAHS patients were correlated positively with apnea hypopnea index (AHI),percentage of sleep time during apnea-hypopnea and percentage of sleep time below 90% oxygen saturation(SaO2 < 90%) respectively(P < 0.05),and those were correlated negatively with the lowest SaO2 and the average lowest SaO2 respectively (P < 0.05). Conclusion:The increasing amplitude of serum PCSK9 and LDL-C levels is interrelated with the degree of OSAHS,and can be seem as clinical predictors of OSAHS combined with cerebral infarction.