The invention discloses a redundant backup-based rope driving system and a control method thereof, and belongs to the field of automatic control and space robots. The rope driving system includes an unfolding line roller, a folding line roller, a line roller reduction box A, a line roller reduction box B, a motor reduction box A, a motor reduction box B, a backup motor gearbox A, a backup motor gearbox B, an unfolding motor, an unfolding backup motor, a folding motor, a folding backup motor, an unfolding rope A, an unfolding rope B and a folding rope. On the basis of normally working motors, the redundant backup-based rope driving system provided by the invention adds the backup motors which can replace main motors to work when the main motors cannot work normally, and when an accident occurs, for example, the system encounters an unpredictable unknown load, when driving force of the main motors is insufficient, the backup motors and the main motors can coordinate with each other and work together, thereby substantially improving operation driving force.