To address the performance degradation of Gussasphalt during thermo-oxidative aging and remelting processes, this study investigates the restoration mechanisms of different additives on the aged and remelted Gussasphalt. Additives including RSS, CAS modifiers, and polymer-modified asphalt were incorporated into aged asphalt to evaluate their effects on performance recovery. The improvement in high- and low-temperature properties, viscosity, and viscoelasticity under remelting conditions was systematically analyzed. Results indicate that the additives significantly increased penetration and ductility, while reducing softening point and viscosity. Among them, a 10% dosage of CAS additive combined with new asphalt exhibited the optimal performance restoration. RSS additive enhanced the plastic deformation capacity of remelted asphalt, whereas CAS and new asphalt improved ductility and softening point, though CAS showed insufficient thermal stability. Viscosity tests demonstrated that 10% CAS addition yielded the most significant reduction in rotational viscosity. Dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests revealed that CAS notably improved phase angle and decreased rutting factor, while RSS showed superior enhancement in low-temperature crack resistance. Comprehensive analysis confirms that the incorporation of appropriate amounts of RSS, CAS, and new asphalt during remelting effectively enhances the properties of Gussasphalt. In particular, CAS additive and new asphalt exhibit outstanding overall performance, contributing to the improved durability and service performance of Gussasphalt.