The conventional thermoelectric(TEG)energy harvesting system exhibits a narrow output power range and cannot collect TEG energy or inefficiently collects the energy under a heavy load. In this study，we proposed a reconfigurable DC-DC converter with maximum energy harvesting to overcome these issues. The proposed method is achieved by using six power switches. Under light load，the TEG supplies power to the load using a boost circuit or stores excess energy to the energy storage battery. Under heavy load，the inductor is charged by the energy storage battery. The TEG discharge circuit is preferentially used for inductive discharge and the energy is converted to the load through the discharge loop to realize the efficient collection of energy under heavy load，and broaden the output power range of the system. Maximum power tracking is achieved through input ripple control，and an adaptive on-time zero-current switching technology is proposed to improve the conversion efficiency. The results obtained under the 180 nm CMOS process indicate that the proposed system exhibits an end-to-end peak conversion efficiency of 92. 34% at an input power of 2. 5 mW，and the TEG can provide 12% of the power to the load when the system works under heavy load(Iload=10 mA).