Abstract: An energy-recycling device and a DC voltage-boosting device thereof is disclosed. The DC voltage-boosting device includes a first phase controller, an interleaved voltage booster, a second phase controller, and a phase-shift voltage converter. The first phase controller generates a first PWM signal and a second PWM signal. The interleaved voltage booster receives an input DC voltage, the first PWM signal and the second PWM signal and increases the input DC voltage to a supplying DC voltage. The second phase controller receives the supplying DC voltage and a setting voltage, thereby generating third PWM signals. The phase-shift voltage converter receives the third PWM signals and the supplying DC voltage and converts the supplying DC voltage into a stable DC voltage.