Abstract: Objective：To evaluate the effect of continuous positive airway pressure (CPAP) on symptoms and the quality of life of patients with mild obstructive sleep apnea hypopnea syndrome (OSAHS) complicated with somnolence.Methods：Seventy-four patients with mild OSAHS were recruited. Epworth sleepiness scale (ESS) was used to evaluate the degree of somnolence. Patients with ESS scores more than ten were designated as somnolence, and CPAP was conducted. Patients with ESS scores less than ten were designated as non-somnolence, and health education was conducted. Quebec sleep questionnaire (QSQ) was adopted to evaluate the quality of life. All patients were followed up for eight weeks.Results：After CPAP treatment, the ESS scores of mild OSAHS patients significantly decreased (P<0.01), and the QSQ scores significantly increased (P<0.01), indicating that CPAP treatment can improve the somnolence and quality of life in patients with mild OSAHS.Conclusions：Patients with mild OSAHS have different degrees of somnolence, which leads to a decline in quality of life. CPAP can improve somnolence and quality of life in patients with mild OSAHS.