A novel phosphorylcholine oligomer-grafted and folate moiety-labeled graphene oxide (GO–PCn–FA) was designed, prepared, and characterized by Fourier transform infrared spectra, nuclear magnetic resonance, Raman spectra, X-ray diffraction, X-ray photoelectron spectroscopy, scanning transmission electron microscopy, transmission electron microscopy, and atomic force microscopy. GO–PCn–FA proved to be an excellent water-soluble and pH-responsive drug carrier for the targeted delivery of doxorubicin (DOX) with a drug loading content of 21%. An in vitro cytotoxicity assay and flow cytometry analysis revealed the superior biocompatibility of GO–PCn–FA compared to normal cells, while DOX-loaded GO–PCn–FA exerted efficient eradication of tumor cells, especially of those with folate receptor expression. An in vivo test showed that GO–PCn–FA was deposited mainly in the pulmonary parenchyma after intravenous administration, and no obvious adverse effect was observed. In summary, phosphorylcholine oligomer-grafted graphene oxide was developed for targeted drug delivery with optimal biocompatibility.