A power converting apparatus with dynamical driving adjustment includes a rectifying unit, a power factor correction unit, a power conversion unit and a feedback unit. The rectifying unit rectifies an AC input power to generate and transfer a DC power to the power factor correction unit for performing power factor correction. A power factor correction power is generated and transferred to the power conversion unit. The feedback unit is electrically connected to the power conversion unit to form a closed control loop. A PWM driving controller of the power conversion unit performs an adjustment process to control a switching transistor based on a feedback signal from the feedback unit, and the power conversion unit converts the power factor correction power into an output power supplied to an external load. Thus, the margin for electromagnetic interference is increased, and both switching loss and conduction loss are considerably reduced.