The invention relates to the field of medical instruments, and provides a multifunctional stomach tube and an initialization method for a pressure detection unit of the stomach tube. The stomach tube comprises a duct, a first channel for conveying nutrient solution is arranged in the duct and provided with a plurality of flow injection holes led to outside, the flow injection holes are formed in the conveying direction of the nutrient solution at intervals, an intraesophageal pH (potential of hydrogen) value detection unit, a temperature detection unit and the pressure detection unit are arranged outside the duct, a monitoring device comprises a main control module, an operator sets relevant parameters by the main control module, and the main control module is used for processing, displaying and recording data information acquired from detection units, 5cm position of upper portion of the lower esophageal sphincter and a pH value of the inside of the stomach are detected, crowds with aspiration risks can be rapidly identified, the temperature detection unit is additionally arranged on a nasopharyngeal area, so that clinical daily body temperature monitoring is facilitated, infected patients are timely found, pressure variation of air bags can be monitored through the pressure detection unit, so that intraesophageal pressure is reflected, and intrapleural pressure is further calculated.