To achieve the co-delivery of doxorubicin (DOX) and small interfering RNA (siRNA) targeting B-cell lymphoma 2 (siBcl-2), lactose acid (LA) and all-trans retinoic acid (ATRA) double grafted N,N,N-trimethyl chitosan (TMC) nanoparticles (GTA NPs) were developed. The relative viability of QGY-7703 cells was decreased to 81.3% when the concentration of GTA NPs was 0.1 mg/mL, but no toxicity to normal cells was observed, indicating that the GTA NPs selectively inhibited the proliferation of tumor cells. With DOX loaded into the hydrophobic core and siRNA condensed onto the hydrophilic shell, GTA/DOX/siRNA NPs were prepared. The GTA/DOX/siRNA NPs possessed high cellular uptake via receptor-mediated endocytosis. Owing to multiple cooperative antitumor effects of DOX, siBcl-2, and GTA NPs, GTA/DOX/siRNA NPs had superior in vitro and in vivo antitumor efficiency to other formulations. These findings provide a guideline for the combined applications of multiple synergistic antitumor manners.