The invention discloses an application method and system of hybrid power. The application method comprises the following steps: before a vehicle runs upslope, an initiative energy supply mode is selected, so that energy is stored; when the vehicle runs upslope, an energy release mode is selected, an accelerator pedal is stepped down, a forward gear position is adopted, and the released energy assists the vehicle to run upslope; when the vehicle runs downslope, an auxiliary brake mode is selected, the forward gear position is adopted, resistance torque is provided, and downslope energy is absorbed. According to the application method and system disclosed by the invention, the stored energy is released so as to assist the vehicle to go upslope or stop the vehicle to go forward when the vehicle goes downslope, so that the gradeability of the vehicle is increased, the brake distance of the vehicle is reduced, and fuel oil is saved.