The invention discloses a large-scale aircraft rear-fuselage digital assembly system comprising a front portion posture adjusting and positioning unit, a vertical fin posture adjusting and positioning unit, bevel angle bases, three layers of operating ladders and posture tracking devices. The front portion posture adjusting and positioning unit is used for posture adjusting, positioning and locking of the front portion of the rear fuselage. The vertical fin posture adjusting and positioning unit is used for posture adjusting, positioning and locking of wall boards of the vertical fin abut jointing area of the rear fuselage. The bevel angle bases are located on two sides of the rear fuselage and are provided with seventh shafts and industrial robots moving along the seventh shafts. The operating ladders are located surround the rear fuselage and are used for operating corresponding positions of the rear fuselage manually. The posture tracking devices are mounted on the periphery of the rear fuselage and are used for tracking dynamically and displaying posture adjustment and posture evaluation during posture adjustment of the rear fuselage. According to the system, a plurality of laser trackers are adopted for measuring measuring points of the rear fuselage, the measured results are input into an integrated management system, a control system executes corresponding adjustment of rear-fuselage mounting part postures, and dynamical tracking and posture adjustment and posture evaluation displaying during posture adjustment are realized.