The invention relates to automation of an electric power system, and particularly to an integrated transformer with functions of voltage boosting and power flow controlling. The integrated transformer comprises a dual-winding transformer, wherein the dual-winding transformer, wherein the dual-winding transformer comprises a primary side winding with an adjustable winding and an autotransformer, and a primary side winding with an adjustable winding, wherein the primary side adjustable winding and the secondary side adjustable winding are accessed to the electric power system and used as a voltage boosting transformer and a power flow regulator of the electric power system. By adoption of the integrated transformer with the functions of voltage boosting and power flow controlling, a voltage source with adjustable amplitude and phase is connected at the head end of the system in series equivalently; and the function of the voltage source is close to that of a unified power flow controller (UPFC), so that the active and reactive power flow of the system can be independently adjusted. An on-load tap changer regulation technology is adopted, so that flexible regulation way and high reliability are achieved. The voltage-boosting transformer and the power flow regulation apparatus of the system are integrated into a whole body, so that the cost is low, and the occupied area is small.