Abstract: Under the optimum experimental conditions, a rapid and sensitive method using purge and trap-gas chromatographic electron capture detection was developed and applied to the determination of trihalomethane in water. Calibration curves of bromodichloromethane, chlorodibromomethane and bromoform were obtained by analyzing their serial standard solutions. In addition, the precision, accuracy, recovery and selectivity were validated. The results indicated that the recovery, correlation coefficients and detection limits of three trihalomethane were in the range of 93.17% ~ 103.00%, 0.998 ～0.999 and 2.660,2.310,2.773 μg/L, respectively.