Objective To investigate the high-risk factors of obstructive sleep apnea hypopnea syndrome (OSAHS). Methods A retrospective analysis was carried out in 190 OSAHS patients admitted in the sleep medical center from March 2016 to March 2018. According to their apnea hypopnea index (AHI), they were divided into mild group (5-15 times/h, n=54), moderate group (16-30 times/h, n=57) and severe group (>30 times/h, n=79). The results of portable sleep breath monitoring (PM) were compared among the 3 groups, and the risk factors of OSAHS at different severities were analyzed by multinomial logistic regression. SPSS statistics 22.0 was used to perform the statistical analysis. Analysis of variance or Chi-square test was employed in intergroup com-parison for different data types. Results Significant differences were found in AHI, minimum oxygen saturation, mean oxygen saturation, oxygen reduction index and number of apnea among the 3 groups (P<0.05). Multinominal logistic regression analysis showed that age at 40-50 years was the risk factor for mild and severe OSAHS (OR=5.740,95%CI 1.657-19.930, P=0.006; OR=0.120, 95%CI 0.025-0.575, P=0.008). Age >50 years was the risk factor of mild OSAHS (OR=3.325,95%CI 1.036-10.674, P=0.043). Neck circumference was a risk factor for OSAHS at all severities. Body mass index (BMI) was a risk factor for moderate and severe OSAHS (OR=0.832,95%CI 0.694-0.996, P=0.045; OR=0.903,95%CI 0.777-1.051, P=0.018).Conclusion Neck circumference is a risk factor of OSAHS at all severities. BMI is associated with the aggravation of OSAHS. Close attention should be paid to them for the control of OSAHS.