To meet the demand for fast conversion of Buck converter from standby or light load to large load state, based on the dynamic performance of the Buck converter with the traditional average current control method, the improved hybrid control strategy with sliding mode controller and PI controller suitable for DCM/ CCM process is proposed. According to the system state and conduction mode, the PI controller or the sliding mode controller is utilized in the voltage outer loop. In addition, the PI controller is used in the steady-state condition, which is then converted to the sliding mode controller according to the conduction mode in the dynamic condition of the load increase. Furthermore, the accurate judgment of the conduction mode is realized by the unified corrected average inductance current. Thus, the proposed hybrid control strategy can effectively combine the steady-state and dynamic performance advantages of PI control and sliding mode control. The simulation and experimental results show that, compared with that of the traditional average current control, the dynamic response time of this strategy is reduced by about 65% and the voltage drop is reduced by more than 35% .