Class E inverter is the most widely used single-ended switching inverter in the high-frequency field. However, due to the existence of resonant network, the inverter can only work under a fixed duty cycle and the output voltage is not adjustable. To solve this problem, this paper proposes a duty-ratio-independent Class E inverter. By solving the circuit equation, the parameters of the resonant element can be derived. Under the determined component value, the output voltage gain corresponding to different duty ratios can be obtained. Finally, a 24 V input, 20 MHz prototype is built to verify the feasibility of proposed method. Simulation and experimental results show that with the proposed method, the inverter can maintain soft switching under different duty ratios, and the output voltage of the inverter can be dynamically adjusted.