Under the background of energy crisis and environmental issues, the high-gain DC-DC converter is indispensable in renewable energy applications. A dual-switch quadratic structure is proposed to enhance the voltage gain of the traditional quadratic boost converter while reducing the current stress of switches. On this basis, by combining the switched capacitors and a coupled inductor, a dual-switch quadratic high-gain DC-DC converter with a couple inductor is put forward. This converter has advantages such as a very high voltage gain, a pair of switches with the same phase, low voltage stress of switches and output diode, and zero-current switching off in many diodes. The operating principle and steady-state performance of the converter are analyzed in detail, including the voltage gain derivation and the voltage and current stresses of components. Finally, a 120 W prototype was fabricated to verify the theoretical analysis and the feasibility of the converter.