The process of absorption of water by way of wood in 3-dimensions can be described mathematically by analytical solutions, whether initial conditions aren’t simples e.g., when there is a profile of concentration at the beginning of a stage of absorption, only numerical model scan be used. The transport of water is then obtained below the fiber saturation point. The potential which drives the transport of the bound-water and the free-water through the wood has been considered by testing a diffusional transport model. The transient diffusion with a constant diffusivity has been tested to describe the process. Analytical solutions have been successfully used to describe the stage of absorption. A model based on numerical method with finite differences has been found to describe the process and especially when the equilibrium of absorption has not been attained and diffusion coefficient parameter in the models was obtained by fitting the model predictions with the experimental data. Finally, water absorption of the studied wood was proved to follow the kinetics of a transient regime.