A composite sound absorbing meta-structure consisting of an embedded Helmholtz resonator and a gradient-perforated porous material (EHGP) is proposed. The acoustic absorption performance of composite structure is analyzed based on the double porosity theory and the finite element method, and the effects of the structural parameters of the embedded neck, the shape of the perforation on the acoustic absorption performance are discussed. The results show that compared with the homogeneous porous material and embedded Helmholtz resonator, the EHGP proposed fully combines the acoustic effects of the two in the low-frequency bandwidth, and achieves perfect acoustic absorption at 265 Hz, in which the absorption coefficient is greater than 0.5 in the bandwidth as high as 155 Hz, while the size of the structure is only 1/25 of the wavelength. Unlike conventional Helmholtz resonators, the gradient-perforated porous material in the composite structure bears more energy loss instead of embedding the neck, giving it a broadband sound absorption capability. Finally, the low-frequency broadband design scheme is experimentally verified. The sound-absorbing meta-structure proposed in this paper provides a new solution in the field of low-frequency noise control at the sub-wavelength scale.