The piezoelectric energy harvester can provide continuous power supply to low-power sensor nodes after rectification through an interface circuit. However, conventional diode-based rectifier circuits suffer from high conduction voltage drops and switching losses, which can lead to startup failure under weak vibration conditions. Moreover, some high-efficiency interface circuit designs rely on external auxiliary power sources, limiting their applicability in practical scenarios. Therefore, this paper proposes a self-powered parallel synchronized switch harvesting on inductor circuit based on synergistic rectification using diodes and MOSFETs (DM-PSSHI). The interface circuit facilitates bidirectional low-loss conduction by integrating MOSFETs and diodes, concurrently achieving low-voltage startup of the rectification module. Additionally, a self-powered peak detection (PKD) switch is employed, eliminating the need for an external bias source. The single-inductor design further reduces circuit complexity and enhances integration potential. Under 21.6 Hz excitation and a 100 kΩ load, the DM-PSSHI circuit outputs 1.68 mW, achieving 2.12 times the power of the standard energy harvesting (SEH) circuit. This significantly enhances the output power of the piezoelectric energy harvesting system.