Neurofilament (NF) is a cytoskeletal filament that is expressed almost exclusively in neuronal cells and assembled from three distinct molecular weight proteins: NF-L, NF-M, and NF-H. The exact nature of the assembly of NF as well as the precise mechanism by which NF regulates axonal diameter and maintain distinctive cytoskeletal organization is not well understood. We performed Monte Carlo simulations to understand the structural behavior of NF qualitatively using a residue-based molecular model of NF. The molecular model of NF systems consists of three primitive models representing NF backbone (rigid rod), side arms (freely-jointed hard-spherical chains), and small ions (hard spheres). We discuss the structural properties such as density profile, mean-square radius of gyration of each type of side arms and also the effects of Ca²⁺ ions or ionic strength.