The invention belongs to the technical field of design of integrated circuits, and relates to an active diode of an adaptive conduction resistor. The active diode of the adaptive conduction resistor comprises a switching tube module, a comparator module and a logic and control unit module; the output end of the switching tube module is electrically connected to the input end of the comparator module; the output end of the comparator module is electrically connected to the input end of the logic and control unit module; and the output end of the logic and control unit module is electrically connected to the input end of the switching tube module. Due to adaptive change of the active diode conduction resistor, the current zero crossing point detection precision of the active diode can be improved; the input range of the active diode is expanded; and thus, the active diode, which is low in conduction voltage drop, high in current zero crossing point detection precision and wide in input range, can be realized.