The mucous layer on the surface of human digestive tract is a dynamically balanced protective system, mainly containing mucin, enzymes, bicarbonate, epidermal growth factor and other protective factors. It has been found that mucins can protect epithelial cells from infection, dehydration, and physical, mechanical or chemical damage. There are a variety of disturbances that affect or destroy the function of the mucous layer, including mucus dysfunction and diseases of digestive tract. In this paper, the mechanical function of mucin on the surface of esophagus was studied using the UMT Tribometer with the porcine esophagus as the experiment sample. Trypsin was used to control the mucin content on the surface of esophagus. Results showed that the trypsin can affect the function of the mucin on the surface of esophagus. The friction coefficient and the relevant energy dissipation of trypsin-treated and non-trypsin-treated samples were significantly different. Due to the reduction of mucin on the esophageal surface by trypsin treatment, the friction coefficient and energy dissipation of the esophageal surface were significantly higher than that of the samples without trypsin treatment. During the friction test, the esophagus surface was severely damaged at both macro and micro scales after trypsin treatment, which indicated that the mucin can play a lubrication role at the gastroscope device-esophagus interface. The results can provide reference for clinical endoscopic examination and medical advice for clinical practice.