A molecular model is proposed for the dynamics of polymer chains in dilute polymer solutions containing well-dispersed low volume fraction spherical particles. The equilibrium structure of the reversibly adsorbed layer was characterized by a scaling theory. The dynamics of the polymer chains is studied by a Maxwell type kinetic model. The results show that at the limit of small particle size, the increase of the monomer-filler energetic affinity, particle volume fraction, and surface friction of the particles can strongly affect the overall viscoelastic response of the filled solutions and lead to peculiar properties such as a dramatic increase in shear viscosity, intense shear thinning, and solid-like behavior at low frequency domains, all of which have been observed experimentally.