A parameter identification circuit for a digital power converter having an inductor and a capacitor, can include: an inductor parameter circuit that receives an inductor current of the inductor, a capacitor voltage of the capacitor, a duty cycle in a start-up stage, and a predetermined inductor current, where the inductor parameter circuit obtains an inductor parameter according to an integrated value of the capacitor voltage, an integrated value of the duty cycle in the start-up stage, and the predetermined inductor current, when the inductor current rises to a level of the predetermined inductor current; and a capacitor parameter circuit that receives the inductor current, the capacitor voltage, and a predetermined capacitor voltage, where the capacitor parameter circuit obtains a capacitor parameter according to an integrated value of the inductor current and the predetermined capacitor voltage when the capacitor voltage rises to a level of the predetermined capacitor voltage.