The invention relates to a cast-in-place ballast bed slab type ballastless track ballast bed slab integral replacement method and belongs to the technical field of high-speed railway ballastless trackstructure maintenance and repair. The method includes the basic procedure that after a ballast bed slab needing to be integrally replaced is determined, ribs are embedded in non-replaced ballast bedslabs at the two ends of the to-be-replaced ballast bed slab in a certain range, transverse line run-through cutting is conducted on the two ends of the to-be-replaced ballast bed slab, a new ballastbed slab integrally prefabricated offline in advance and provided with reserved connecting ribs is used for integrally replacing the existing ballast bed slab under a transverse track shifting condition, and finally, track structure longitudinal connection and integrity are recovered. Under the condition that steel rails are not cut off, diseases of the ballast bed slab, sleepers and the interfaces of the ballast bed slab and the sleepers of a cast-in-place ballast bed slab type ballastless track are quickly eradicated in an offline prefabrication and online integral replacement mode, the quality is guaranteed, meanwhile, the method can be suitable for various ballast bed slab forms, and the integral replacement requirement of the ballast bed slab of a single line, a large longitudinal slope and a large ultrahigh section under a special working condition can be met.