Well-redispersed ceria nanoparticles (CeO₂ NPs) were synthesized by a simple hydrothermal method. The prepared CeO₂ NPs exhibited excellent catalytic activity towards classical peroxidase substrate 3,3,5,5-tetramethylbiphenyl dihydrochloride (TMB·2HCl) in the presence of H₂O₂, based on which a colorimetric method that is highly sensitive and selective was developed for glucose detection. The composition, structure, morphology and peroxidase-like catalytic activity of CeO₂ NPs are investigated in detail by using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FT-IR), thermal analysis (TG) and UV-vis absorption spectroscopy. According to this method, the detection of H₂O₂ and glucose are in linear range from 6.0 × 10⁻⁷ to 1.5 × 10⁻⁶ mol L⁻¹ and 6.6 × 10⁻⁶ to 1.3 × 10⁻⁴ mol L⁻¹, with the detection limit down to 5.0 × 10⁻⁷ mol L⁻¹ H₂O₂ and 3.0 × 10⁻⁶ mol L⁻¹ glucose, respectively. Further, this simple, cheap, highly sensitive and selective colorimetric method for glucose detection was successfully applied for the determination of glucose in human serum samples.