A novel chemiluminescence (CL) flow system for the determination of sulfite is described. It is based on the direct CL reaction of sulfite and silver(Ⅱ) in acid media without any sensitizers. The unstable Ag(Ⅱ) is on-line electrogenerated via a positive Pt-electrode from AgNO3 in HNO3 medium by constant current electrolysis, resulting in the elimination of the inconvenience of its instability to water. The CL intensity emission intensity was linear with sulfite concentration in the range 4×10−7-1×10−5mol/l; the detection limit was 1.7×10−7mol/l (3). The system was applied satisfactorily to the determination of sulfite dioxide in air.