The present invention relates to a trench gate IGBT device and a manufacturing method thereof, and belongs to the power semiconductor device technology field, and relates to an insulated gate bipolar transistor. According to the present invention, by introducing a composite trench structure and a carrier storage layer which are coupled mutually, and introducing an electrode connected with an emitter at the bottom of a gate electrode of an injection enhanced gate transistor (IEGT) device, on one hand, the depth and width of the gate electrode are reduced under a certain trench depth and width, on the other hand, by the shielding effect of the introduced electrode connected with the emitter, the gate capacitance, especially the gate-collector capacitance of the device is reduced, the switching speed of the device is improved, the switching loss of the device is reduced. Meanwhile, by introducing the coupled carrier storage layer, the adverse effect to the positive conduction characteristic of the device which is caused by introducing the gate electrode connected with the emitter is compensated, further the carrier concentration distribution of a whole drift region is improved, and the better compromise of the device positive conduction voltage drop and the switching loss is obtained.