Addition of nanosized particles to a polymer solution/matrix can lead to new and improved properties over conventional composites using larger filler particles. In this work, we investigated systems of nanoparticles and polymer using Brownian dynamic simulations. The shape of the nanoparticles was considered to be spherical and the polymer architecture was modeled as bead spring chains. The degree of dispersion and agglomeration in the system were characterized by mean square displacement. Various factors, including size of nanoparticles, nanoparticle-polymer interaction, polymer chain length, and relative volume fractions, affect the dispersion of nanoparticles in the polymer matrix. In this study, the influence of polymer chain length and size of nanoparticles were analyzed and presented.