Abstract: This paper presents a physically based method to simulation the mechanics of a fluid flowing through porous deformable materials. We introduce Darcy's law to governing fluid absorption and diffusion. Over-saturated part of porous solid loses excess fluid by dripping. Contrary to previous wetting simulation approaches, we extend the diffusion model, with which fluid can transport in and between porous materials. Thus, our method is capable of simulating imbibition of fluid into porous solids and surface flow over different porous surfaces. In our algorithm model, physical properties are affected upon four stages, including fluid-solid coupling, fluid absorption, diffusion and over-saturation. Results show that our method provides various new effects and better computational efficiency.