A high-speed PWM control apparatus with adaptive voltage position and a driving signal generating method thereof is provided. The present invention automatically detects a change in the loading and adjusts the voltage position instantaneously for stabilizing the voltage and reducing the loading output power consumption. The present invention does not require a clock signal to generate a driving signal and does not require an error amplifier to control the modulation. Therefore, the present invention has a fast transient response that responds to the change of the loading instantaneously and has a stabilizing effect. When the apparatus is on a continuous conduction mode (CCM), the switching frequency of the controller is still fixed even though the input voltage Vin and the output voltage Vout are changed. The electrical-magnetic noise disturbance is improved.