A novel polymer of poloxamer188--PCL was synthesized via a ring-opening polymerization. Fourier transform infrared spectroscopy (FTIR), Raman, and H nuclear magnetic resonance (H NMR) spectra were used to study the structures of obtained poloxamer188--PCL. The thermo-stability of poloxamer188 --PCL was carried out with a thermal gravimetric analyzer (TGA), and cytotoxicity was obtained using the CCK8 method. Cargo-free and curcumin (CUR)-loaded poloxamer188--PCL NPs were fabricated via the solvent evaporation method. The morphology, particle size distribution, and stability of cargo-free NPs were studied with a scanning electron microscope (SEM) and laser particle analyzer. The radioprotection activity of CUR-loaded NPs was performed. FTIR, Raman, and H NMR spectra confirmed that poloxamer188--PCL was obtained. TGA curves suggested poloxamer188--PCL had better thermo-stability than original poloxamer188. Cell tests suggested that the cargo-free NPs had no cytotoxicity. SEM image showed that the cargo-free NPs were spherical with a diameter of 100 nm. Free radical scavenging experiments proved that CUR-loaded NPs had better antioxidant activity than CUR solutions. CUR-loaded NPs could be detected in all tissues, including liver, kidneys and lung. In summary, this work demonstrated a feasibility of developing an injective formulation of CUR and provided a protection agent in caner radiotherapy.