A resonant switching power converter includes: a first power stage circuit; a second power stage circuit; a controller; and a current sensing circuit configured to sense a first charging/discharging resonant current flowing through a first charging/discharging inductor of the first power stage circuit and sense a second charging/discharging resonant current flowing through a second charging/discharging inductor of the second power stage circuit, to generate a corresponding first current sensing signal and a corresponding second current sensing signal, respectively. The controller adjusts at least one of a first delay interval, a second delay interval, a third delay interval, a fourth delay interval, and/or input voltages, according to a first current sensing signal and a second current sensing signal, so that a constant ratio between an output current of the first power stage circuit and an output current of the second power stage circuit is achieved.