Overexpressed P-glycoprotein (P-gp), as the key factor in multidrug resistance (MDR), can greatly reduce intracellular drug levels as a result of chemotherapeutic drug efflux out of cancer cells. Although various P-gp antagonists have been developed to circumvent the MDR effect, the common strategies of physical entrapment or chemical conjugation of anticancer drugs may inevitably induce unstable circulation in vivo or poor response in cancer cells, greatly limiting the therapeutic efficacy. Herein a double-drug-based supramolecular complex (DDSC) was first constructed based on the host-guest interactions between two active drugs, curcumin (Cur)-bridged bis(β-cyclodextrin) and ferrocene-linked camptothecin (CPT). Supramolecular dual drug nanomicelles (SDDNMs) formed by the DDSC self-assembly are proposed to work against the MDR effect, in which Cur as a P-gp antagonist in combination with CPT realized stable transport in vivo and efficient stimuli-responsiveness in cells. In vitro and in vivo studies further confirmed that SDDNMs effectively circumvented the drug efflux induced by the MDR effect and remarkably enhanced the synergistic therapeutic effects.