A new self-assembly method for the fabrication of periodic structures using monodispersed polystyrene nanoparticles matrix was developed. The self-assembly could be formed into polystyrene nanoparticles matrix constructed by the face centered cubic (FCC) structure and hexagonally close-packed (HCP) monolayer. The polystyrene nanoparticles have been prepared by emulsion polymerization. Several aspects were investigated by using different techniques: Particle sizer, TEM and DSC etc. In this study, the feasibility of synthesizing nanoparticles of 550 nm polystyrene with a perfect spherical shape and a narrow size distribution was demonstrated. Subsequently, an investigation of the self-assembly of polystyrene nanospheres to built up an opal structure was performed. This arrangement was achieved by gravitational sedimentation under vacuum. The face centered cubic structure was identified by using SEM, thus that the different facet type {100}, {110} and {111} were composed. The self-assembly of monodispersed polystyrene nanoparticles in 2D structure was fabricated in the structure of hexagonally close-packed monolayer.