Box-type integrally-prefabricated building module connecting structure and building system

The invention discloses a box-type integrally-prefabricated building module connecting structure and a building system, and relates to the technical field of constructions. The box-type integrally-prefabricated building module connecting structure comprises a first horizontal box module and a second horizontal box module, and at least one horizontal connecting assembly, the first horizontal box module and the second horizontal box module are horizontally connected through the horizontal connecting assembly, the horizontal connecting assembly comprises a horizontal mortise and clamping teeth arranged in the horizontal mortise, and the clamping teeth are arranged on the side portion of the first horizontal box module, the horizontal mortises are formed in the side portions of the second horizontal box modules, the second horizontal box modules are provided with a plurality of first connecting bolts at the positions of the horizontal mortises so that the clamping teeth can be fixedly connected into the horizonta