In recent years, using magnetic nanocomposites for controlled release of drugs and target-specific drug delivery has great potential in exploring a new method for cancer chemotherapy. Nevertheless, the low loading rate of insoluble drugs greatly restricts their efficacy and clinical application. Here, an efficient magnetic nanostructure combining FeO nanoparticles and layered double hydroxide (LDH) was developed and used for tumor cell inhibition. LDH was first deposited on FeO nanoparticles (FeO@LDH), curcumin (Cur) was then loaded and polydopamine (PDA) eventually formed a PDA-coating on FeO@Cur-LDH via self-polymerization. The FeO@Cur-LDH/PDA nanostructure showed a suitable nano-meter size, excellent magnetic property, and high drug loading rate (up to 38 %). In vitro release results implied that FeO@Cur-LDH/PDA nanostructure had good pH-responsive performance and excellent controlled-release behaviors due to the introduction of PDA. The cellular experiments demonstrated that FeO@Cur-LDH/PDA nanostructure had good biocompatibility. In addition, FeO@Cur-LDH/PDA entered into the cells mainly through endocytosis and had excellent inhibition on HepG2 cell viability in a concentration-dependent manner. Therefore, FeO@Cur-LDH/PDA nanostructure has a prospective application in cancer therapy as a controlled drug delivery system.