This paper investigates low-frequency acoustic absorption mechanism of a viscoelastic layer with resonant cylindrical scatterers. The viscoelastic layer is 20 mm-thick, and the cylindrical scatterer is a cylindrical cavity coated with a soft rubber layer, with axis in the lateral layer direction. The absorption properties of the viscoelastic layer under the steel-backing condition are studied using the layer-multiple scattering method. Results show excellent absorption performance in the frequency region of 1000–3000 Hz. The absorption mechanism is investigated by analyzing the absorption cross-section of a single scatterer and the multiple scattering of a periodic array of scatterers, together with the displacement field and power dissipation density. Effects of the resonant absorption of a single scatterer and the coupling resonance between the absorption layer and the steel-backing are revealed.