The invention discloses a hybrid power transmission mechanism for driving a clutch to be separated and combined, which is connected with a hybrid power automated manual transmission (AMT) in parallel, and a gear shifting method. The transmission mechanism is arranged behind an engine and the clutch and before the AMT and comprises a hybrid power driving motor and a planetary gear set which are connected; a screw section matched with a release bearing pushing block of the clutch is extended in the center of a planet carrier; a clutch brake is arranged on the planet carrier; and the gear shifting method comprises the following steps of: combing and separating the clutch and keeping, purely outputting power by the motor in the separation state of the clutch, driving an automobile to run or generating electricity by only taking the engine as power and driving a vehicle to run by only taking the motor and the engine as a power source, recovering part of braking energy, and controlling a gear shifting process. In the hybrid power transmission mechanism, a synchronizer is saved, integrated level is relatively high, the mass of the transmission and the cost are reduced, and the reliability of the hybrid power and the AMT control is improved.