Abstract: As shown by the results of a comparative study on the methods of capillary column-gas chromatography with ECD and ceric sulfate-catalytic spectrophotometry for the determination of iodide in water,the former method was preferred for its merits of simplicity in operation,a broader range of determination (0.19-100 μg·L-1),better accuracy and precision (values of RSD′s (n=6) of 0.89%-3.11%,and recovery in the range of 95% to 104%,both for 3 different concentration levels) and lower value of detection limit (3S/N) (0.19 μg·L-1).In addition,no interference was observed by the presence of Cl- ion and heavy metal ions,and by variation of temperature and time of reaction in the GC method.