The invention discloses a rectifying circuit used for energy obtaining. The circuit comprises a first PMOS tube, a second PMOS tube, a first active diode, a second active diode, and an energy-storage capacitor. A source electrode of the first PMOS tube is connected with a source electrode of the second PMOS tube, and the connected source electrodes are used as an output end and are connected with one end of the energy-storage capacitor. A grid electrode of the second PMOS tube, a drain electrode of the first PMOS tube, and a cathode of the first active diode are connected and are used as a first input end. A grid electrode of the first PMOS tube, a drain electrode of the second PMOS tube, and a cathode of the second active diode are connected and are used as a second input end. Anodes of the two active diodes and the other end of the energy-storage capacitor are connected with ground. Input of the rectifying circuit is connected with an energy harvester, and output supplies power for a load through a DC-DC converting circuit. The rectifying circuit is characterized by self-power-supply, zero bias, and zero static power consumption, power consumption of the circuit is effectively reduced, and range of electric power extraction from the energy harvester is expanded, so that efficiency of energy obtaining is improved.