The invention discloses an injection enhanced gate transistor (IEGT)-based high-capacity water-cooled modular H-bridge structure for a converter. The H-bridge structure is symmetrical in leftward and rightward directions, and comprises a box type frame, a left-phase module unit, a left capacitance module, a bypass module, a voltage crowbar circuit, an isolated power supply, a left discharging resistor, a left water-cooled resistive radiator, a left module driving unit, a water outlet pipe, a water inlet pipe, a left-phase module water inlet branch pipe, a left-phase module water outlet branch pipe, a left control unit, a left power unit and a left charging unit, wherein the left-phase module unit and the left capacitance module are positioned on left front and rear parts of the left side in the frame respectively; the bypass module and the voltage crowbar circuit are positioned on the middle parts of the front and rear parts in the frame respectively; the isolated power supply is fixedly arranged on the rear part of the frame; the left discharging resistor is fixedly arranged on the left side of the rear part of the frame; the left water-cooled resistive radiator is fixedly arranged on the left discharging resistor; the left module driving unit is connected to the front end of the left-phase module unit; the water outlet pipe and the water inlet pipe are transversely arranged on the upper and lower parts of the rear part of the frame respectively; and the left control unit, the left power unit and the left charging unit are sequentially and fixedly arranged from front to back on the left side of the frame. The H-bridge structure can be applied to various high-voltage high-capacity converters, is light and simple in structure and convenient to assemble, debug and maintain, and can be modularly produced in batches, and the high-voltage high-capacity installation requirements of modern power electronics can be met.