A parallel resonant converter including a control circuit and at least two resonant conversion circuits connected in parallel between an input bus and an output bus is provided by the invention. The control circuit is configured to provide a switching frequency signal to the at least two resonant conversion circuits. Moreover, the control circuit is further configured to control the voltage of the output bus to linearly vary along with the switching frequency signal in a rated range by using a linear current-balancing curve (gain-frequency), and thus achieving the purpose of current-balancing for the at least two resonant conversion circuits. The invention is capable of controlling the output voltage of the parallel resonant converter, so as to reduce the ripple on the output voltage of the power supply system.