Recent progress in fifth-generation (5G) communication systems has increased the demand for flexible electromagnetic interference (EMI) shielding materials with high absorption capability and long-term stability. Herein, we report a bilayer EMI shielding film consisting of a thermoplastic polyurethane/carbonyl iron powder (TPU/CIP) absorption layer and a carbon nanotube/poly(2,5-bis(3-dodecylthiophen-2-yl)thieno[3,2-b]thiophene) (CNT/PBTTT) reflection layer. This bilayer architecture synergistically integrates strong magnetic and dielectric losses in the absorption layer with precisely controlled conductivity in the reflection layer, leading to absorption-dominant EMI shielding behavior. As a result, the film exhibits a low reflection shielding effectiveness (SER) of 3 dB and a high absorption shielding effectiveness (SEA) of 55 dB. Notably, the composite retains over 95% of its total shielding effectiveness (SET) with a reflection coefficient (R) below 0.5 even after 10,000 folding cycles, demonstrating excellent mechanical durability. Furthermore, thermal stability tests reveal that more than 90% of the initial SET is preserved, accompanied by negligible changes in R, after exposure to 150 °C for 1 h. These results demonstrate that the proposed bilayer film is a promising flexible, absorption-dominant EMI shielding material for next-generation high-frequency applications