A meta‐absorber is a type of metamaterial capable of absorbing incident electromagnetic waves, primarily used for isolating and attenuating these waves. Due to their unique properties, meta‐absorbers are widely used in areas of electronic shielding, radar cross‐section reduction, as well as military camouflage. To enhance the working bandwidth, conventional meta‐absorbers integrate multiresonance modes in different layers, resulting in increased thickness and limiting their applications. Herein, a multiplexing integration meta‐absorber is proposed in a one‐layer planar board, achieving an ultrathin thickness of 0.053 λ and an ultrawide absorption band covering the whole X and Ku bands (8.0–18.0 GHz) by harnessing the coupling of four resonant modes. Moreover, the designed meta‐absorber is insensitive to the polarization of incident waves and exhibits good angle stability within ±45°. The experimental results agree well with the simulations. These findings may inspire the development of ultrathin metadevices with multifunctionalities operating across different frequency domains.