The main component of bourdon pressure gauge is a spring tube bent into a circular arc, and the cross section of the tube is oval. One end of the spring tube as a measuring element is fixed and connected with the measured medium through a joint; the other end is closed and is a free end. The free end is connected with the connecting rod and the sector gear, and the sector gear engages with the movement gear to form a transmission amplification device. The spring tube pressure gauge uses the elastic deformation of the sensitive elements (Bourdon tube, bellows, bellows) in the watch, and then the pressure deformation is transmitted to the pointer by the conversion mechanism of the movement in the watch, causing the pointer to rotate to display the pressure.