The objective of this thesis is to investigate the effect of resonant inductor on the performance of phase-shift full-bridge DC converter. It shows that the inductance value will affect the resonance as well as the zero-voltage-switching turn-on feature. To achieve zero-voltage-switching, the inductance value is related to the parasitic capacitance of power device and the square of input voltage. A phase-shift full-bridge DC converter has been designed and implemented. The specifications of this converter as following: input voltage = 156 V/DC, output voltage = 48 V/DC and output power = 0.5 kW. The experimental results show that the maximum efficiency is 89.38% and the efficiency at full load is 87.71%. This result proves the theoretical analysis.