A method for detecting halogenated organic substances in landfill leachate and polluted water bodies thereof, by combined solid phase extraction method comprising HLB solid phase extraction and PPL solid phase extraction, the aqueous samples are enriched by solid phase extraction using an HLB solid phase extraction column and a PPL solid phase extraction column, respectively, the enriched samples are then subjected to FT-ICR MS detection, and two detection data of FT-ICR MS are subjected to molecular formula matching of organic molecules, molecular screening, molecular information summarization, and/or statistical analysis of the data of samples, respectively, and the two are combined to obtain all dissolvable halogenated organic substances in the samples of water.