Framework connecting piece and modular substation prefabricated cabin

The invention relates to the technical field of prefabricated cabin type substations, in particular to a framework connecting piece and a modular substation prefabricated cabin. The framework connecting piece comprises a plurality of connecting piece bodies which are mutually combined or singly used, and the connecting piece bodies are used for positioning square steel; the connecting piece body comprises a foundation plate, a first flange plate, a second flange plate, a force bearing plate and a transmission mechanism, a power input point of the transmission mechanism is arranged at the center of the foundation plate, and a power output point of the transmission mechanism is arranged at the first flange plate; the square steel acts on the power input point, the transmission mechanism is used for transmitting power of the power input point to the power output point, and power of the power output point acts on the force bearing plate so that the force bearing plate can apply prestress to the square steel. Ther