A Fe³⁺-OPD chromogenic system was developed based on the formation of yellow and fluorescent product from direct oxidation of OPD via Fe³⁺, which was selected from investigation on the oxidation ability of different metal ions (Fe²⁺, Fe³⁺, Cu²⁺, Zn²⁺, Al³⁺, Na⁺, Ca²⁺, Mg²⁺, K⁺, Ag⁺, Cr³⁺) towards o-phenylenediamine (OPD). A colorimetric method for selective detection of sulfide was then developed combining the reducibility of sulfide and its strong affinity towards metal ions. The results showed that, in NaAc-HAc buffer solution at pH 4.0, the absorbance and fluorescence intensity of Fe³⁺-OPD chromogenic system showed a good linear relationship with NaHS concentration ranging 10~ 200 μmol/L and 5~150 μmol/L, respectively. The fluorescence method exhibited a detection limit of 0.1 μmol/L with no observed interference from other reducing substances and thiols. The paper-based colorimetric system, constructed from Fe³⁺-OPD chromogenic system in combination with test paper, displayed a good linear relationship between blue color value (B value) and the concentration of NaHS in the range of 20~150 μmol/L, and a detection limit of 2 μmol/L. The paper-based colorimetric system was further applied for sulfide quantification in spiked tap water and fetal calf serum.