Abstract: Objective To investigate the esophageal sphincter pressure changes of achalasia (AC) patients at various ages using high resolution esophageal manometry (HRM) and provide evidences for its physiopathologic mechanism and treatment. Methods Clinical data about 146 patients with achalasia who had undergone HRM at our Digestive Endoscopic Center from November 2014 to November 2015 were retrospectively analyzed.All patients were divided into three groups: group A (young group: ≤44 years, n=85), group B (middle-aged group: 45-59 years, n=41) and group C (older group:≥60 years, n=20).Clinical characteristics and HRM data were compared between three groups. Results The prevalence of AC in male patients declined significantly with the increase of age (group A vs group C: 50.6% vs 20.0%, P=0.013).Integrated relaxation pressure (IRP) of lower esophageal sphincter in young group was significant higher than older group (29.78±9.72) mmHg vs (24.75±7.11) mmHg (1 mmHg=0.133 kPa), P=0.032, while, the incidence of abnormal LES resting pressure was significantly higher in young group than older group (32.9% vs 10.0%, P=0.041).Furthermore, upper esophageal sphincter (UES) resting pressure in young group was significant higher than older group (75.92±32.45) mmHg vs (53.27±22.17) mmHg, P=0.004.The incidence of low UES resting pressure was significantly higher in older group than young group (30.0% vs 5.9%, P=0.006).Conversely, the incidence of high UES resting pressure were significantly higher in young group than older group (18.8% vs 0, P=0.006). Conclusion Achalasia mostly occurs in young and middle-aged person.The prevalence in male declines significantly with the increase of age.Compared with older group, patients in young group show higher LES integrated relaxation pressure and higher UES resting pressure.