Abstract: In a medium of 0.06 mol·L-1 H2SO4,chemiluminescence (CL) intensity of the CL reaction between KBrO3 and luminol was significantly enhanced by the presence of S2- ion.By applying flow-injection technique to this CL-reaction system,a novel method for determination of sulfide ion was proposed.Linear relationship between magnitude of CL-intensity and mass concentration of S2- ion was found in the range of 1.0×10-6-1.0×10-3g·L-1 (in 3 concentration segments),with its detection limit (3s/b) of 8.0×10-7g·L-1.Precision of the method was tested with standard sulfide solution of 1.0×10-4g·L-1 for 11 determinations,giving value of RSD 3.4%.The proposed method was applied to the analysis of water samples,and using these samples as matrixes,recovery was tested by the standard addition method.Values of recovery found were in the range of 96.5% to 105.0%.