Abstract: Objective: To analyze the risk factors affecting the occurrence of carotid atherosclerosis (CAS) in patients with obstructive sleep apnea hypopnea syndrome (OSAHS),and to develop and validate the corresponding nomogram model. Methods: Patients with suspected OSAHS admitted to the outpatient department of the hospital were selected,and divided into a CAS group and a non-CAS group based on the presence or absence of CAS through diagnostic screening.The clinical data of patients in the two groups were compared.Multiple logistic regression analysis was used to identify effective influencing factors,a nomogram model was drawn,and the efficacy of the model was validated. Results: There were statistically significant differences in body mass index (BMI),diastolic blood pressure,systolic blood pressure,history of hypertension,history of hyperlipidemia,history of alcohol consumption,C-reactive protein,and severity of OSAHS between the two groups (P<0.05).Multivariate logistic regression analysis showed that BMI≥25 kg/m²,history of hypertension,history of hyperlipidemia,C-reactive protein≥12.55 mg/L,and severity of OSAHS were the influencing factors for the occurrence of CAS in OSAHS patients (P<0.05).The area under the ROC curve was 0.890 (95%CI:0.810-0.971),the maximum Youden index was 0.608,sensitivity was 0.859,and specificity was 0.879. Conclusions: BMI≥25 kg/m²,history of hypertension,history of hyperlipidemia,C-reactive protein≥12.55 mg/L,and severity of OSAHS are closely related to the occurrence of CAS in OSAHS patients.The nomogram model constructed based on this can be used as one of the risk screening tools.