Abstract: A method for identification of the interrelated impurities in some kind of chain extender for polyurethane, hydroquinone bis(2-hydroxyethyl)ether (HQEE) industrial products by gas chromatography-time of flight mass spectrometry(GC-TOFMS) was developed. 50mg HQEE samples was dissolved in 50mL iso-propyl alcohol, and injected into HP-5 capillary column (30m×0.25mm×0.25μm). Three peaks from the total ion current chromatogram of HQEE samples were qualitatively confirmed by comparing with the retention time and MS spectrum of HQEE standard. The results showed that three main impurities were accurately identified to be homologeous compounds with the relative molecular mass of 154, 242 and 286, respectively. Under selected GC/TOFMS conditions, all components were fully separated. According to the synthesis process, the structures of the three impurities were proposed. The practical amount of ethylene oxide in the sample synthesis was in-vestigated. The method will help to effectively control and improve product quality in HQEE synthesis.