The layered double hydroxide (LDH) was grown in situ on the surface of montmorillonite (MMT) by hydrothermal method, and the layered double hydroxide@montmorillonite (LDH@MMT) was obtained. LDH@MMT was characterized by XRD, SEM, FTIR and other means, and the results showed that LDH and MMT were compounded together through hydrogen bonds, forming a flower-like structure. The layered double hydroxide@montmorillonite/modified zanthoxylum bungeanum seed oil (LDH@MMT/MZBMSO) was prepared by introducing LDH@MMT into zanthoxylum bungeanum seed oil(ZBMSO). TEM results showed that LDH@MMT was evenly dispersed in MZBMSO. Appling LDH@MMT/MZBMSO to the leather fatliquoring process, compared with MZBMSO, When the quality of LDH@MMT accounts for 12% of ZBMSO, the flame retardant performance of LDH@MMT/MZBMSO treated crust leather was significantly improved, and the oxygen index of crust leather increased from 22.8% to 28.3%, the after flame time was reduced from 87 s to 43 s, the heat release rate, total heat release rate, and smoke production rate of LDH@MMT/MZBMSO treated crust leather were reduced by 43.6%, 73.6%, and 63.5%, respectively. LDH@MMT wrapped on the surface of the crust leather fiber to form a "torrtuous path" that could slow down the release of heat and smoke, a dense carbon layer was formed on the surface of the fiber to further block the heat and smoke released, and isolated oxygen during the burning process of the crust leather, thus improving the flame retardant and smoke suppression performance of the crust leather.