The invention relates to a method for preparing hydrophilic graphene, and belongs to the field of inorganic materials. The method comprises the following processes of: oxidizing natural flake graphite serving as a raw material by a Hummers method to obtain graphite oxide; dispersing the obtained graphite oxide into deionized water and performing ultrasonic processing to make the graphite oxide peeled into single-layer graphene oxide sheets; adding an appropriate amount of hexamethylene tetramine in a mass ratio of the graphite oxide to the hexamethylene tetramine of 2:1-1:2; and performing reflux reaction for 8 to 12 hours at the temperature of 100 DEG C with stirring to obtain a graphene dispersion system which is stably dispersed in water. The method has the advantages of simple process, convenient operation and low preparation cost.