Abstract: Chemiluminesence reaction of potassium permanganate I^- formaldehyde system was investigated, and a new method for determination of micro amounts of iodine was developed. The effects of factors e.g consistency of various reaction mass, acidity, disturbing ions, etc. on the analytical results were studied. Under optimal condition, the linear range for the determination of I^- was 1.0×10^-6 ～4.0×10^-5 g/mL and the detection limit was 2.4×10^-8 g/mL, the relative standard deviation for the determination of 1.0×10^-5 g/mL I^- (n=11) was 2.8%.