Abstract: A method for analysis of chlorinated hydrocarbons and aromatics hydrocarbons in natural water and soil samples by selected ion monitoring GC-MS (SIM) with internal standardization was developed. The analytes in the samples were separated and pre-concentrated by solid phase extraction. The analytical results show that the average errors for the analytes are within 25% in water samples and within 10% in soil samples and the analytical errors enlarge with the decrease of the analyte concentration.