Carbon quantum dots (CQDs) were synthesized by a one-step hydrothermal method with maple leaves as raw materials.The structure and optical properties of CQDs were characterized through high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectrum, thermogravimetry and UV-Vis absorption spectrophotometry.The results show that CQDs with amorphous structures mainly consist of C, H, O, N elements.Their surfaces are rich in functional groupssuchasC＝C, C＝O, C—H, C—N and N—H.They emit blue fluorescence under excitation of ultraviolet light and have excitation-dependent properties.The fluorescence intensity reaches a maximum at an excitation wavelength of360 nm, corresponding to a fluorescence emission wavelength of 438 nm.CQDs exhibit high fluorescence stability under high ionic strength conditions, indicating that they can be used in biomarker and analytical detection fields.