LLC resonant converter is widely used in medium- and high-power applications. Because of its resonant characteristics, soft switching and the increase of power density can be realized easily. To increase power density and improve output capacity, an asymmetric half bridge interleaved parallel output LLC resonant DC-DC converter is designed. The working process of the converter is analyzed. The influence of different k values on converter is analyzed, and equivalent analysis of resonant network is carried out. Under different resonant frequencies, converters are distributed in different working areas, and the accomplishment level of soft switching process of switching MOS transistor is different. Simulation and prototype test show that the converter can realize zero voltage switch (ZVS). The switching loss of converter is effectively reduced.