Sound absorbing porous materials are widely used for protection and insulation applications. In recent years, the development of recyclable bio-based porous materials have aroused a great interest to replace petroleum-based traditional materials. This work aims for studying, in particular, acoustic properties of a novel bio-based porous epoxy resin obtained by an adapted combination of cationic photopolymerization and porogen leaching technique. A multiscale framework was proposed for studying the acoustic absorption performances of a plate-like panel made of this kind of material. To do so, the asymptotic homogenization method was first used to estimate the effective properties of the elaborated material, which has fillet-edge cubic pore shapes according to the SEM (Scanning electron microscope) images. The finite element method was used to solve the cell problems and compute the effective properties. The sound absorption of a plate made by the equivalent poroelastic material with rigid impervious backing under a normal incidence was then studied. The validation was done by comparing the numerical estimation of equivalent dynamic density and bulk modulus to corresponding experimental results obtained by using the three-microphone impedance tube testing on several elaborated samples. A parametric study was carried out to investigate influence of the porosity, the pore arrangement, and the pore size on effective properties and sound absorption performances of the material. The obtained results should be very useful for improve the elaboration process of these materials in order to optimize, in particular, the sound absorption performances of isolation structures.