Multifunctional drug delivery systems (DDS) with simultaneous multimodal therapeutic and stimuli-responsive capabilities are recently of considerable interest. Herein, a versatile DDS capable of glutathione (GSH)/pH responsivity was engineered for the effective drug delivery and chemo-photothermal synergistic effects. Polydopamine (PDA) and polyethylene glycol (PEG) were coated on the surface of degradable dendritic mesoporous silica nanoparticles (DDMSNs) to construct the dual-responsive and photothermal nanoplatform, coined as DDMSNs-DOX-PDA-PEG. The developed nanocarriers presented excellent GSH/pH responsivity due to PDA coating and tetrasulfide bonds imbedded in DDMSNs can be broken under in low pH and high GSH concentration environment, implementing the controlled drug release. Specifically, the DDS showed better stability, biocompatibility and photothermal properties owning to the modification of PDA and PEG, and the nanocarriers performed an efficient cell uptake and significant tumor permeability efficiency. Furthermore, upon near-infrared laser irradiation, the cyto-inhibition for 4T1 cells was enhanced evidently via a synergism of chemo-photothermal treatment. Therefore, the proposed DDMSNs-DOX-PDA-PEG has great potential as DDS for effective drug delivery and the synergistic treatment of chemo-photothermal therapy. As expected, the developed strategy provides a facile alternative for fabricating multifunctional DDS for tumor therapy.