Objective Gas chromatography-mass spectrometric （GC-MS） with positive chemical ionization technique （PCI） was developed to detect nine haloacetic acids in drinking water.Methods The samples were extracted by methyl tert-butyl ether， derived by acidified methanol， and analyzed by GC-MS with PCI source under selected ion monitor mode. The matrix-matched calibration curve internal standard method was used for quantification.Results The nine haloacetic acid compounds showed good linear relationship in the range of 0.2-100 μg/L， with the correlation coefficients over 0.99. And the limits of quantification （S/N=10） ranged from 0.107 to 1.640 μg/L. The average recoveries of nine haloacetic acid compounds were 81.8%-110.2%， and the relative standard deviations were 3.9%-8.8%.Conclusion The method has good precision and sensitivity， and can be used for the determination of haloacetic acid compounds in drinking water.