Abstract: A method for tracking power supplies includes the following steps: receiving, by a controller, a signal to be tracked and outputting, according to the signal to be tracked, a control signal. The control signal controls at least two sets of voltage level selection circuits in selecting at least one tracking voltage level from at least two groups of isolation voltage levels and controls each set of the voltage level selection circuits selecting at most one tracking voltage level from a group of isolation voltage levels. An isolation power supply provides the at least two groups of isolation voltage levels according to the voltage level interval of the signal to be tracked. Each group of isolation voltage levels includes at least two tracking voltage levels. The voltage level selection circuits provide the selected tracking voltage level to supply power to a load circuit. An apparatus for tracking power supplies is also provided.