The invention discloses a dual-input and high-gain BOOST converter. The dual-input high-gain Boost converter comprises two DC input sources, a variable-structure switch block composed of three switches, two power switch tubes, a coupling inductor with four windings, eight one-way rectifier diodes, and an output filter capacitor. Compared with the existing BOOST converter, the dual-input and high-gain BOOST converter disclosed by the invention still can work as normal when one DC input source cannot work as normal; under the same duty ratio, the greater boosting transformation ratio is provided, the power switch tube voltage stress is low, the control policy is simple, and the volume is small.