Objective To prepare a honokiol (HNK)-loaded zein nano-drug delivery system with low biotoxicity and to investigate its inhibitory effect on MDA-MB-231 breast cancer cells.  Methods Zein-HNK nano-drug delivery system was prepared by anti-solvent method . The particle size, dispersion, morphological characteristics, encapsulation efficiency and in vitro release behavior of the system were investigated. The effects of this system on the proliferation, apoptosis, migration and invasion of MDA-MB-231 cells were evaluated.   Results The particle size of Zein-HNK was (83.75±2.95) nm and the polymer dispersity index(PDI) of it was 0.132±0.015. The encapsulation efficiency of HNK was (93.04±1.86)%. The in vitro release rate of Free-HNK group was(88.90%±2.58)% and release rate of Zein-HNK group was (69.10±1.88）% at 24 hours. Cytotoxicity evaluation showed the 50% inhibiting concentration(IC₅₀) of MDA-MB-231 cells in the positive control group was (5.02±0.29) mg/L, which of MCF-7 cells was (4.72±0.22) mg/L; and the IC50 of MDA-MB-231 cells in Zein-HNK group was (9.92±1.02) mg/L, which of MCF-7 was (9.35±0.30) mg/L. The apoptotic rates of control group, Zein-HNK group and Free-HNK group were (8.73±0.64)%, (15.05±0.85)% and (28.54±1.48)%, respectively. Migration index was 0.67±0.04 in the control group, 0.55±0.03 in the Zein-HNK group and 0.36±0.03 in the Free-HNK group (P<0.05). The relative number of invasions was 0.66±0.03 in the control group, 0.44±0.01 in the Zein-HNK group and 0.35±0.03 in the Free-HNK group (P<0.01). Western bltting result showed that Zein-HNK induced cell apoptosis by decreasing the expression of Bcl-2 and increasing the expression of Bax.   Conclusion Zein-HNK nano-drug delivery system can effectively reduce the toxic and side effects of HNK itself. Zein-HNK nano-drug delivery system can effectively inhibit breast cancer proliferation, induce cell apoptosis, and inhibit cell migration and invasion simultaneously.