A power supply method and apparatus for dual power load includes a low voltage direct current-direct current converter (LDC) configured to convert a voltage of a high-voltage battery to supply power, a first low-voltage battery configured to be charged by receiving the power from the LDC and to supply power to a general load or a dual power load, a second low-voltage battery configured to be charged by receiving the power from the LDC and to supply power to the dual power load, a first relay disposed between the LDC and the first low-voltage battery, a second relay disposed between the LDC and the second low-voltage battery, a first battery sensor configured to measure a voltage of the first low-voltage battery, and a second battery sensor configured to measure a voltage of the second low-voltage battery.