Abstract: A method of solid phase extraction with magnetic polystyrene-Fe₃O₄ (HCP-Fe₃O₄) combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was established, which was used to determine the content of bisphenol A (BPA) in water. After extracted by HCP-Fe₃O₄ and eluted by methanol, water samples were separated by ACQUITY UPLC BEH C₁₈ column, with the mixtures of methanol and water with the different volume ratios as mobile phase for gradient elution. The electrospray ionization source of MS in negative ion (ESI^-) mode was used for detection under the mode of multiple reaction monitoring (MRM). Linearity relationship between values of mass concentration of BPA and its peak area was kept in the range of 1.000-1 000 μg·L^-1, with limit of detection (3S/N) of 0.04 μg·L^-1. Values of the spiked recovery were found in the range of 98.4%-99.9%, and RSDs (n=6) of the measured values were found in the range of 2.6%-8.2%.