In this study, stable water-based heat transfer nanofluid containing a kind of three-dimensional porous graphene (3D PG) has been prepared. For dispersion of 3D PG in water, it is hydrophilic treated by an alkaline method, which is a facile and effective approach in preparing water-soluble graphene by introducing the carboxyl groups (-COOH) as a mild oxidation process using potassium persulfate. The stability and thermal conductive performance of the nanofluid have been investigated with different loading at various temperatures. Experimental results show that the nanofluid can remain highly stability and its enhanced thermal conductivity up to 8-34% can be observed even at lower weight fraction of 0.01-0.07 wt% at room temperature.