The invention fully discloses a control method for the power assembly of a hybrid electric vehicle. The power assembly of the hybrid electric vehicle comprises an engine and a motor which are coaxially connected, under the unified coordination of HCU, by using the output torque of the EMS control engine and the output torque of the MCU control motor, the working model of the power assembly is divided into the followings modes: an engine automatic start/stop mode, an auxiliary drive mode, a power-generating mode and a regenerative braking model, wherein, the auxiliary drive mode can be divided into a performance auxiliary drive mode and an efficiency auxiliary drive mode by HCM according to the condition of SOC battery. Therefore, the scheme ensures that SCO battery is in an optimum state, thereby not only ensuring that the regenerative braking mode is charged, but also ensuring that a sufficient electric energy can be used for driving the automobile and starting the engine under the engine automatic start/stop mode, and meanwhile, ensuring that the engine is always under a small waste delivery volume and works in a small fuel consumption region.