Due to the excellent photoluminescent properties and singlet oxygen (1O2) generating efficiency, graphene quantum dots (GQDs) with maximal emission in near-infrared region (NIR) exhibited great potential in cancer imaging and therapy. However, GQDs can be cleared quickly via the renal system in vivo because of their ultrasmall size, which leads to the compromised cancer cell killing efficacy. Here, we report a hybrid nanoplatform, where GQDs were incorporated into the cavity of hollow mesoporous silica nanoparticles (hMSN) to form GQDs@hMSN-PEG nanoparticles (NPs). Optical characterization indicated that GQDs@hMSN-PEG NPs still maintained good absorption and emission properties from GQDs, and the composite NPs still possessed similar 1O2 generating efficiency. GQDs@hMSN-PEG NPs exhibited good biocompatibility in vitro and in vivo. High cargo-loading efficiency was achieved for doxorubicin (DOX), and the formed GQDs@hMSN(DOX)-PEG NPs showed the feasibility of tumor-oriented drug delivery. The extended retention time in tumor and good drug loading efficacy confirmed that GQDs@hMSN-PEG could serve as one promising candidate for combinational cancer treatment where photodynamic therapy and chemotherapy modules can be integrated into one system.