The invention discloses a preset jacking apparatus for handling a bridge-head jump problem by the use of an adjustable lapping slab. The apparatus comprises a refitted maintenance vehicle (1), a lapping slab (2), external threaded rods (6), a laser leveling device (7), a preset bearing platform and a low-frequency electric wrench. The external threaded rods (6), the laser leveling device (7) and the low-frequency electric wrench are arranged on the refitted maintenance vehicle (1); the lapping slab is provided with multiple jacking holes (13) and grouting holes (14); each jacking hole is internally provided with a threaded sleeve (5); and the lapping slab is placed on the preset bearing platform. During a jacking process, the external threaded rods (6) abut against upper portion bearing platform block grooves (15) and are engaged with the internal threaded sleeves (5), the lapping slab is jacked, the laser leveling device (7) indicates that the lapping slab (2) and the road are on the same plane, the gap formed during the jacking process is filled with grout through the grouting holes (14) by a grouting device, and normal traffic can be restored after the grout solidifies. The jacking apparatus is designed in a preset manner, is high in generality, is convenient to construct, and is low in cost.