A seat adjustment system for a vehicle seat is provided. The seat adjustment system includes a seat body; at least one actuating unit, configured to adjust a support of the seat body; a sensing unit, configured to obtain and provide seat information and body shape data of a back of an occupant; and a control unit, configured to control the at least one actuating unit; wherein when one parameter of the seat body changes, the control unit makes a portion of the body shape data of the occupant in a pre-defined range via the at least one actuating unit.