The invention discloses a reinforcement and deviation rectification method by combining horizontal foundation replacement and pile body jacking, belongs to the field of foundation reinforcement and deviation rectification, and can solve the foundation reinforcement and deviation rectification problem of an ancient building on a broken loose foundation with poor integrality. The method comprises the following steps that a guide pit is excavated on the periphery of the building, an original foundation of the building is excavated in the guide pit, and is replaced with prefabricated reinforced concrete plates, then the plurality of prefabricated reinforced concrete plates are pulled tightly by using split screws, a ring beam is arranged on the peripheries of the prefabricated reinforced concrete plates, and finally, the weak broken original foundation is replaced by using a complete reinforced concrete plate foundation; and a jack is arranged just below the new foundation to push a steelpipe pile downwards into the stable rock stratum section by section, the uneven settlement and the building inclination are rectified, and finally the foundation replacement, reinforcement and deviation rectification of the inclined ancient building with the non-uniform settlement problem are completed. According to the method, the construction speed is high, required manpower and material resources are small, the disturbance to the upper building is smaller and safer, and the integrity and stability of the reinforced concrete plate foundation after the final replacement is completed are bothhigher than the integrity and stability of a foundation by using other replacement methods.