Abstract: In order to establish a rapid detection method for Fe³⁺, the kiwifruit biomass carbon dots (CDs) were prepared by microwave method with kiwifruit juice as carbon source and ethylenediamine as surface modifier. The CDs were rich in -OH, -NH and C-O groups, had an average particle size about 2.5 nm, which were soluble in water and stable. The CDs emitted blue fluorescence under 365 nm ultraviolet light. A new and rapid detection method for Fe³⁺ was established with the CDs based on the fluorescence quenching effect of Fe³⁺. When the addition amount of Fe³⁺ from 0.2 to 10 μmol/L, the fluorescent intensity (F/F₀) of CDs decreased linearly with the increase of Fe³⁺(R²=0.9934), and the limit of detection (S/N=3) was 0.12 μmol/L. This detection method was applied to the determination of Fe³⁺ content and the recovery was 98.82%～103.20% , RSD was between 1.67% and 2.05%. The operation of this detection method was simple, rapid and strong selective.