A shower door sliding mechanism for soft positioning, comprising a track component disposed in a fastening manner, a movable door piece, a pulley component, and a flexible closer component movably disposed in the track component by using the pulley component, wherein the flexible closer component comprises a fastening bracket and a flexible closer having a bayonet, the flexible closer is fastened to the fastening bracket, and the fastening bracket is connected and fastened to the pulley component and located between two pulley components; the track component comprises a track having a longitudinal passage therein and a positioning component that is fastened to the track and that can be coupled to the bayonet; the longitudinal passage is surrounded by an upper wall, a lower wall, a front wall, and a rear wall of the track, the longitudinal passage comprises a positioning component receiving groove and a sliding groove in which the flexible closer component and the pulley component can move, the positioning component receiving groove and the sliding groove extend in the longitudinal direction of the track and are distributed adjacently in the lateral direction of the track, and the lower wall has a longitudinal opening and a sliding surface (105, 106) supporting the pulley component; and a glass clamp component is disposed at the top of the movable door piece characterised in that the top of the glass clamp component is connected to a threaded hole in the pulley component by using an adjusting screw, so that the movable door piece is integrally suspended directly below the flexible closer component and the pulley component; wherein the glass clamp component comprises a first glass clamp piece and a second glass clamp piece, the first glass clamp piece and the second glass clamp piece are assembled and fastened to the movable door piece by using mutually fitted threaded holes (9011, 9021) and screws, stepped semicircular holes (9012, 9022) are further disposed in the first glass clamp piece and the second glass clamp piece, the adjusting screw comprises a threaded cylinder with a square step and a circular step disposed at the bottom thereof, and the square step and the circular step fit with a circular hole formed by the stepped semicircular holes (9012, 9022) in the first glass clamp piece and the second glass clamp piece, so that the movable door piece is suspended at a lower end of the adjusting screw by using the glass clamp component, the threaded cylinder at an upper portion of the adjusting screw fits with and is connected to the threaded hole in the pulley component, and the square step is twisted by using an open-end wrench, to adjust the height of the movable door piece. the flexible closer component comprises a fastening bracket and a flexible closer having a bayonet, the flexible closer is fastened to the fastening bracket, and the fastening bracket is connected and fastened to the pulley component and located between two pulley components; the track component comprises a track having a longitudinal passage therein and a positioning component that is fastened to the track and that can be coupled to the bayonet; the longitudinal passage is surrounded by an upper wall, a lower wall, a front wall, and a rear wall of the track, the longitudinal passage comprises a positioning component receiving groove and a sliding groove in which the flexible closer component and the pulley component can move, the positioning component receiving groove and the sliding groove extend in the longitudinal direction of the track and are distributed adjacently in the lateral direction of the track, and the lower wall has a longitudinal opening and a sliding surface (105, 106) supporting the pulley component; and a glass clamp component is disposed at the top of the movable door piece characterised in that the top of the glass clamp component is connected to a threaded hole in the pulley component by using an adjusting screw, so that the movable door piece is integrally suspended directly below the flexible closer component and the pulley component; wherein the glass clamp component comprises a first glass clamp piece and a second glass clamp piece, the first glass clamp piece and the second glass clamp piece are assembled and fastened to the movable door piece by using mutually fitted threaded holes (9011, 9021) and screws, stepped semicircular holes (9012, 9022) are further disposed in the first glass clamp piece and the second glass clamp piece, the adjusting screw comprises a threaded cylinder with a square step and a circular step disposed at the bottom thereof, and the square step and the circular step fit with a circular hole formed by the stepped semicircular holes (9012, 9022) in the first glass clamp piece and the second glass clamp piece, so that the movable door piece is suspended at a lower end of the adjusting screw by using the glass clamp component, the threaded cylinder at an upper portion of the adjusting screw fits with and is connected to the threaded hole in the pulley component, and the square step is twisted by using an open-end wrench, to adjust the height of the movable door piece.