Abstract: The granular matter is a large assemblage of densepacking particles. The interparticle forces are usually dominant incomparison with drag forces from interstitial fluid, and are transmittedthrough heterogeneous force chains. This paper studies themultiscale structures and rate-dependent processes involved in granularmaterials, and shows that the granular matter is a typical multiscalemechanical system. Three length scales are identified, particle, force chainand granular system in micro- meso- and marco scales, respectively, andwith three related characteristic time scales. The correlation ofparticle-force chain, force chain-system would be the major problem in themultiscale analysis of granular materials.