To minimize wear and tear on the transmission components of rotary energy harvesters, this work proposes a synchronous rotary piezoelec. energy harvester based on magnetic gear (SR-PEH).The magnetic gear, consisting of an excitation wheel and a response wheel, facilitates synchronous rotation through magnetic coupling.Each wheel is equipped with corresponding piezoelec. patches, forming two distinct sets of piezoelec. energy harvesters, designated as PEH1 and PEH2.Furthermore, the transmission between the two wheels is interrupted when the rotational speed exceeds a specific threshold, preventing potential damage to the device.Consequently, this transmission system provides the advantages of contactless transmission, zero wear, and high transmission efficiency.The results of theor. analyses and experiments indicate that under optimal structural configurations, the maximum voltages of PEH1 and PEH2 are 25.54 V and 49.985 V, resp., resulting in a combined voltage of 71.33 V when connected in series.This represents a 279.29% increase in voltage compared to PEH1 alone.In addition, the SR-PEH can reach a maximum output power of 2.37 mW, when the rotor speed is 900 r/min and the external resistance is 200 kΩ.The SR-PEH can effectively harvest wind and water flow energy through a turbine.