In order to investigate the effects of electroosmosis on chemical and mineral compositions of soil, a laboratory electroosmotic consolidation test was carried out using kaolin as an example. The soil samples and drainage water samples before and after the one-dimensional electroosmotic consolidation experiment were collected. The mineral and chemical composition of soil samples were measured using the X-ray diffraction and X-ray fluorescence spectrometry techniques, and the chemical composition of the water samples were measured with inductively coupled plasma mass spectrometry(ICP-MS). The variations of chemical composition in the soil and water samples and the migration phenomenon of different elements during the electroosmosis process were analyzed. The results show that, of the main mineral constituents of kaolin, the dickite content changed significantly, while the quartz, kaolinite, and nacrite contents changed little. The main chemical constituents in the soil samples, SiO₂ and Al₂O₃, did not show obvious change after electroosmosis. There were large changes in CaO, MgO, Na₂O, and K₂O, of which the variation of CaO was the most significant. The analysis of water samples shows that Na and K tended to flow into water in the form of ions, and Ca and Mg tended to generate hydroxide precipitation, which meant that the Ca and Mg ions could not be detected easily.