A dual-source energy harvesting system based on self-triggered flyback converter (STFC) topology is proposed to extract energy from piezoelectric transducers (PZT) and thermoelectric generators (TEG) simultaneously. The passive module of the STFC circuit can extract energy from the PZT and TEGs at the peaks of PZT voltage. The active module can be triggered to extract energy from the TEGs efficiently during the off-peak time of the PZT voltage and can realize the maximum power extraction of TEGs. The measurement shows that the output power of the STFC circuit is 3.72 times of that without TEG.