A lifting-adjusting assembly for a shaft has an outer device, an inner device and multiple positioning elements. The outer device is adapted to mount around a shaft and has a base and a mounting casing. The mounting casing is mounted around the base and has a chamber, an opening and a cone surface. The inner device is movably connected to the outer device and has a moving mount and at least one spring. The moving mount is movably mounted in the outer device and has a mounting chamber, a pressing segment and multiple positioning holes. The at least one spring is mounted in the chamber to enable the positioning holes to face to the cone surface. The positioning elements are mounted in the positioning holes of the moving mount and abut with the cone surface and the shaft to hold the lifting-adjusting assembly on the shaft.