An adaptive power converter controller coupled to a load and a power converter circuit is provided. The adaptive power converter controller has an adaptive voltage sensing unit and a converting control circuit. The adaptive voltage sensing unit is coupled to the load and output a voltage sensing signal according to a load current and a load voltage from the load. The converting control circuit is utilized for receiving the voltage sensing signal and comparing the voltage level of the voltage sensing signal with a current sensing signal, which is corresponding solely to the load current, so as to decide whether the power converter circuit is controlled according to the voltage sensing signal or the current sensing signal.