 This research developed a new type of ultra-thin and flexible EMI shielding material made up of carbon nanotubes, emzine, and cellulose nanofibers. It has excellent mechanical properties, including a tensile strength of 97.9 MPa and a fracture strain of 4.6%, as well as high electrical conductivity and EMI shielding effectiveness. Additionally, it features a sandwich structure which allows for improved EMI shielding effectiveness and a gradient structure which regulates the contributions from reflection and absorption. This research is significant in developing ultra-thin and flexible composite materials for highly efficient EMI shielding performance and expanding the potential applications of emzine-based composite materials. This article was authored by Wintao Chao, Chen Ma, Xiaotan, and others.