Abstract: Objective To investigate the effects of sitting and supine positions on esophageal motility detected by high resolution manometry (HRM) technology. Methods The esophageal motility parameters of sitting and supine positions were monitored from fourteen healthy volunteers by HRM. The UES residual pressure, pharyngeal maximum pressure, skeletal muscle maximum pressure, proximal contraction integral (PCI), distal contraction integral (DCI), systolic forward velocity (CFV), bolus internal pressure (IBP), LES residual pressure, and the integrity of the contraction in both positions were recorded. SPSS17.0 was used to compare the data that were collected by HRM-system. Results The pharynx maximum pressure of supine position was significantly lower than that of sitting position (P< 0.05). UES residual pressure, skeletal muscle maximum pressure, distal contraction integral (DCI), internal bolus pressure (IBP), LES residual pressure of supine position were significantly higher than that of sitting position (P< 0.05). There was no significant difference between supine and sitting position in proximal contraction integral (PCI) and systolic forward velocity (CFV) (P> 0.05). Conclusion Different positions apparently affect esophageal motility under physiological conditions. The impact of position on the monitoring results should be taken into account when monitoring HRM esophageal motility.