To improve the flame retardancy and smoke suppression effect of epoxy resin (EP), a new organic–inorganic hybrid (MH@ZB‐ODOPB) was fabricated. First, hierarchical‐structured particles (MH@ZB) were prepared by gradually depositing zinc borate (ZB) on the surface of magnesium hydroxide (MH) via a heterogeneous deposition process. Second, MH@ZB was modified with 10‐(2,5‐dihydroxyphenyl)‐10‐hydro‐9‐oxa‐10‐phospha‐phenanthrene‐10‐oxide (ODOPB) to obtain MH@ZB‐ODOPB. Finally, the chemical structure and form of MH@ZB‐ODOPB were analyzed via X‐ray diffraction, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and scanning electron microscopy. The characterization results show that ZB was loaded onto the surface of MH, and ODOPB was grafted on the surface of MH@ZB. The cone calorimetry test results show that when 7.5 wt% MH@ZB‐ODOPB was added into EP, the peak heat release rates, total heat release, total smoke production, and peak smoke production rates decreased by 51.8%, 42.4%, 58.1%, and 66.1%, respectively. Moreover, EP/MH@ZB‐ODOPB exhibited a limiting oxygen index of 33%. These results show that the incorporation of MH@ZB‐ODOPB into EP composites considerably improved the flame retardancy and smoke suppression properties of EP composites. The double action of MH@ZB‐ODOPB in condensed and gas phases was investigated by analyzing the carbon residue and pyrolysis gas. Furthermore, the implementation of ODOPB improves the mechanical properties of EP composites.

In order to reduce the emission of smoke and toxic gases during the combustion of epoxy resin (EP), inspired by the structure of “flowers after rain,” a novel low‐cost flame retardant (FMH@ZHS) was prepared by using flower‐like magnesium hydroxide (FMH) as the flower and zinc hydroxystannate (ZHS) as the raindrop. The tensile strength of EP/3FMH@ZHS increased by 13.7% compared with EP/3FMH. Moreover, the 3 wt% FMH@ZHS hybrid material increased the limited oxygen index value of the EP composite to 27.6% while suppressing the dripping phenomenon during combustion, achieving self‐extinguishing characteristic. Meanwhile, compared with pure EP, peak heat release rate, peak smoke production rate, total smoke production, and peak carbon monoxide production rate of EP/3FMH@ZHS decreased by 34.6%, 55.6%, 41.8%, and 50.0%, respectively. The flame retardant mechanism showed that during the combustion process, the catalytic char formation of magnesium oxide, zinc oxide, and stannic oxide generated from FMH@ZSH can promote the formation of a denser and continuous char layer, inhibiting the transport of flammable gases, toxic gases and heat and improving the fire safety of EP composites. In conclusion, this biomimetic material provided a good approach for the industrial application of EP.