Abstract The development of a thin, tunable, and high‐performance flexible electromagnetic (EM) absorbing device that aims to solve signal interference or EM pollution is highly desirable but remains a great challenge. Herein, demonstrated is a flexible electrical‐driven device constructed by an insulated organic‐polymer substrate, carrier transmission layer, and core–shell structured absorber, enabling a narrow and tunable effective absorption region ( f E < 2.0 GHz) by controlling the external voltage toward this challenge. As a key design element, the selected absorber consists of an Sn/SnS/SnO 2 core and C shell, which exhibits an exceptional dielectric‐response ability at a small voltage, which is attributed to desirable carrier mobility and excitable carriers. Multiple f E ‐tuning regions (maximum up to 7.0), covering 90% of C‐band can be achieved for Sn/SnS/SnO 2 @C‐based flexible device by selecting a low voltage (2–12 V). The strategy developed here may open a new avenue toward the design of flexible intelligent EM device for practical applications.