A method of controlling a hybrid power train may include: driving a first input shaft connected to a second motor-generator by the second motor-generator to synchronize a speed of a driven gear of a target gear position with a speed of an output shaft; moving a sleeve to directly connect the second input shaft, the output shaft, and the driven gear of the target gear position; decreasing torque of the first motor-generator and increasing torque of the second motor-generator to converge torque transferred from the second motor-generator to the output shaft, to torque of the output shaft; moving the sleeve to release the second input shaft and maintain only the output shaft and the driven gear; and increasing torque of an engine and decreasing the torque of the second motor-generator to converge torque transferred from the engine to the output shaft, to the torque of the output shaft.