Zwitterionic complexes in aqueous solutions have been extensively explored as the most promising candidate in drug delivery systems for targeted cancer chemotherapy. A POSS-based supramolecular AD-POSS-(sulfobetaine)7/CD-PLLA zwitterionic complex has been fabricated via a combination of efficient click chemistry and host-guest interaction. The well-defined POSS-based zwitterionic polymer could self-assemble into spherical nanoparticles that encapsulated a model cancer drug (DOX) and exhibited drug release in a controlled manner in a faintly acidic environment. On account of the hydrophilic block with cationic and anionic groups in the microscopic range that can form a hydration layer via electrostatic interactions, these drug-loaded nanoparticles exhibited excellent stability in a tumor intracellular microenvironment or under other pH conditions as revealed by dynamic light scattering (DLS) and zeta potential measurements. In vitro experiments demonstrated that these POSS-based nanoparticles had high resistance to non-specific protein absorption and low cytotoxicity against normal cells. Moreover, these DOX-loaded aggregates could be accumulated and effectively internalized by HeLa and MCF-7 tumor cells, exhibiting effective cellular proliferation inhibition via the release of anticancer agents. Therefore, these POSS-based supramolecular amphiphilic zwitterionic complexes, relying on the simple supramolecular interaction and efficient click reaction, could further emerge as a potential universal anticancer drug nanocarrier system for multifunctional cancer chemotherapy.