Abstract: Objective To explore the effects of obstructive sleep apnea hypopnea syndrome（OSAHS）on the aldosterone-renin activity ratio（ARR）of primary aldosteronism（PA）patients. Methods Clinical data of 130PA patients were analyzed retrospectively. The PA patients were divided into OSAHS-PA group（n=31）and simple PA group（n=99）according to the results of polysomnography examination. Baseline data of the two groups were compared. Spearman correlation analysis was used to analyze the correlations of apnea hypoventilation index（AHI）and the lowest oxygen saturation（SaO2）with ARR value. Multiple linear regression was used to analyze the main influence factors of ARR. Results The constituent ratio of male,body mass index（BMI）,diastolic blood pressure,low-density lipoprotein cholesterol（LDL-C）and plasma renin activity（PRA）in OSAHS-PA group were higher than those in simple PA group（all P＜0.05）while age42（37,46）vs 47（41,55）years oldand ARR539（214,1061）vs 1162（549,2236）（pmol/L）/μg/（L·h）in OSAHS-PA group were lower（all P＜0.05）. Spearman correlation analysis showed that there was a negative correlation between AHI and square root of ARR（r=-0.39,P=0.03）and a positive correlation between lowest SaO2and square root of ARR（r=0.37,P=0.04）. Multivariate linear regression showed that male and OSAHS were the main influence factors of square root of ARR（all P＜0.05）. Conclusion OSAHS decreases ARR value of patients with PA. More attention should be paid to avoiding the missed diagnosis of the OSAHS-PA when ARR were used to screen patients with PA.