Objective To investigate features of esophageal motility and gastroesophageal reflux on GERD patients with hiatus hernia (HH) using high resolution manometry and multichannel intraluminal impedance-pH monitoring.Methods Consecutive GERD patients with sliding hiatus hernia diagnosed by endoscopy and X ray were enrolled to small HH without erosive esophagitis (HHs) group, small HH with erosive esophagitis (HHs+EE) group and large HH with erosive esophagitis (HH L+ EE) group after high resolution manometry, through which large HH was defined as the high pressure zone distance between low esophageal sphincter (LES) and cmral diaphragm is more than 3 cm.Another 30 healthy controls (HC) were recruited.