A coupled inductor based on dual switches buck-boost converter is proposed in the article, which can be used in renewable energy applications. Wide conversion ratio can be realized by regulating turns ratio of the coupled inductor and the duty cycle. The topology has a quadratic- like voltage gain, and the low voltage stress and current stress. Combing the passive clamping circuit to recover leakage energy, the voltage spikes of power switches are suppressed, improving the efficiency. Moreover, it has the merits of continuous input current and common ground. To demonstrate the superior performances of the presented converter, the principle of operation and steady-state analysis are presented in detail. At last, a 100 W experimental prototype was designed to verify the correctness of the theoretical analysis, with a maximum efficiency of 95.7% in step-up mode and 96.8 % in step-down mode.