Fluorescent carbon dots(PM-CDs) were synthesized by a simple one step hydrothermal carbonization method with the extract of unripe persimmon(Diospyros Kaki L.f).TEM image showed that the PM-CDs were homogeneous spheres with a average particle diameter about 15.39 nm.XRD revealed that the PM-CDs were a kind of amorphous carbon material like graphene.The elements of PM-CDs were determined by XPS,which contained complicated elements,and the principal elements presented in PM-CDs were in accordance with those in the general CDs.The PM-CDs contained some active groups,such as hydroxyl,carboxyl and amino.There existed an absorbance for PM-CDs at 350 nm,which emitted an excitation dependent fluorescence at a maximum excitation wavelength of 355 nm and a maximum emission wavelength of 445 nm.Meanwhile,the PM-CDs had a pH independent fluorescence,and showed a stable emission peak in a pH range of 5.0-11.0.The PM-CDs had a strong blue fluorescence under UV irradiation at 365 nm.The PM-CDs had higher selectivity toward Fe3+ compared to other co existed metal ions.The fluorescence intensity of PM-CDs had a linear response to Fe3+ in the concentration range of 0.45-50 μmol/L with correlation coefficients(r2) of 0.923 4,which demonstrated that they were available in the detection of Fe3+.It is necessary to further explore the purification technology for CDs from biomaterials,improving the recognition sites for target analytes and obtaining the higher efficiency for detection.