Al2O3@5A zeolite composite was prepared by atomic layer deposition (ALD) to improve its comprehensive application performance. Trimethyl aluminum was used as an aluminum source, water as an oxygen source and nitrogen as carrier gas. Process pressure was 26.6 Pa, deposition temperature was 150 ℃, and cycles were 300. The Al2O3 amorphous thin film with the thickness of about 30 nm was grown on the surfaces of 5A zeolite. The influence of Al2O3 thin film on the mechanical strength and adsorption performance of 5A zeolite was investigated. The Al2O3 thin film is uniformly coated on the surfaces of 5A zeolite, which effectively inhibits the fracture and slag-dropping. The amorphous Al2O3 thin film shows uniform nano-island morphology, leading to excellent hydrophobicity. In addition, the Al2O3 thin film provides more active aluminum, which is conducive to chemisorption with organic pollutant molecules. The surface modification of 5A zeolite was realized by using ALD technique, the obtained unique Al2O3 amorphous film not only improves its mechanical strength and stability, but also enhances the adsorption capacity for organic pollutants.