Mesoporous carbon nanomaterials have found applications in drug delivery and cancer therapy. However, it is still quite challenging to fabricate their multifunctional counterparts with high selectivity and efficiency for cancer theranostics. In this study, an alternative and multifunctional nanoplatform was developed, wherein mesoporous carbon nanoparticles (MCNs) were first encapsulated with a polyacrylic acid (PAA) shell, and after doxorubicin (DOX) loading, a polyethyleneimine (PEI) layer was coated to prevent the leakage of DOX. The MUC1 aptamer (Apt) was subsequently anchored onto the surface to provide the ability for specific recognition of cancer cells. This nanocarrier has been shortly termed as Apt@DP-DOX-MCN. The double polymer shells endowed the drug carrier platform with glutathione (GSH) and pH dual stimuli-responsive capability, and controllable release of the encapsulated drug molecule could be realized from the mesoporous and hollow structure, providing a 60% release of the loaded drug. Considering that most tumor sites exhibit more acidic environments or high redox potential, the pH- and GSH-sensitive release capability is particularly useful for controlled drug delivery in cancer therapy as it takes advantage of the inherent characteristics of tumor cells. The anchored MUC1 aptamer facilitates spatiotemporal therapy to improve selectivity towards the objective lesion site and decrease the off-target toxicity. Moreover, the targeted recognition and therapy of human lung adenocarcinoma cancer cells (A549) and breast cancer cells (MCF-7) was successfully achieved.