The invention discloses a mobile phone glass polishing material preparation method which comprises the following steps: 1) preparing composite powder, namely coating the surface of quartz by cerium oxide by using a chemical precipitation method so as to obtain composite powder; and 2) preparing modified composite powder, namely mixing polyethyleneimine with water, controlling a pH value, and stirring the mixture with the composite powder, thereby obtaining a polishing liquid. The invention further provides a preparation method of a mobile phone glass polishing material. According to the preparation method, the surface of quartz is coated by cerium oxide by using the chemical precipitation method, so that the polishing velocity of the polishing material is remarkably increased; meanwhile asthe surface of powder is modified by using polyethyleneimine, and adsorption of polyethyleneimine with hydroxyl on the surfaces of granules is resulted under the action of hydrogen bonds, propertiesof a liquid surface are conspicuously changed, particle sizes of aggregated particles are reduced, the particle distribution range is narrowed, the powder aggregation phenomenon is reduced, and the dispersion stability of a suspension is remarkably improved.