Highly cross-linked polymeric nanoparticles (CLPN) were prepared via a facile one-step synthesis. These nanoparticles are effective catalyst for CO₂ cycloaddition to epoxides. In this study, CLPN was synthesized by radical copolymerization of 4-vinylbenzyl-tributylphosphorous chloride (PIL) and ethylene glycol dimethacrylate (EGDMA) in selective solvent, such as C1~C5 alcohols. The results revealed that spherical nanoparticles with the mean diameter range of 10–100 nm could be prepared in these alcohols, and the size of CLPN could be facilely tuned by the feed ratio of EGDMA to PIL. CLPN were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermo gravimetric analysis (TGA), atom absorbance spectrograph, and Fourier transform infrared (FT-IR) spectrum techniques. In addition, CLPN can be exploited as highly active and selective catalysts for the cycloaddition of CO₂ to epoxides. The effects of parameters, such as reaction temperature, pressure, reaction time, and catalyst amount, on the cycloaddition reaction were investigated. As a result, excellent yield (100%) and selectivity (100%) of cyclic carbonates could be achieved at mild conditions (0.1 g CLPN, 3.0 MPa CO₂, 140 °C and 3 h) without the addition of any solvents or co-catalysts. Unexpectively, CLPN could be dispersed in the products homogeneously, which resulted in the extremely high activity and selectivity. At the same time, CLPN could be easily separated by filtration after pouring the reaction mixture into toluene. CLPN could be recycled for six times with only less than 1.5% loss of catalytic activity.