Atomic layer deposition was employed for preparation of thiol-functionalized silica as efficient adsorbent of palladium(Ⅱ) ions. Under reaction conditions of 3—5 kPa and 125—150 ℃, trifunctional γ-mercaptopropyltrimethoxysilane(MPTMS), γ-merecaptopropyltriethoxysilane(MPTES) and bifunctional γ-mercaptopropyldimethoxymethylsilane(MPDMMS) were vaporized in an autoclave, and chemically bonded to po-rous silica, respectively. The bonding mode, morphology and thiol group content of the thiol functional silica were characterized by FTIR, solid state 13C and 29Si nuclear magnetic resonance, elemental analysis, TGA, and nitrogen adsorption-desorption analysis. The behavior of the adsorption of Pd(Ⅱ) ions from aqueous solutions at pH=3.0 onto thiol functionalized silica samples was studied by measuring the changes in concentration of Pd(Ⅱ) solution in contact with the silica using spectrophotometry. The results show that bidentate bonding mode is preferred for all three silane reagents and the thiol contents are determined to be 0.84, 0.77 and 0.82 mmol/g, respectively, for MPTMS, MPTES and MPDMMS modified silica. The adsorption of Pd(Ⅱ) ions on MPTMS, MPTES and MPDMMS modified silica could be described by the Langmuir equation with a saturation adsorption capacity of 1.21, 1.04 and 1.14 mmol/g, respectively. The molar ratios of Pd/S were 1.44, 1.35, and 1.39. Thus, both thiol content and adsorption capacity of the materials prepared by atomic layer deposition are higher than those of the bonded silica made by reaction in organic solvent as generally practiced. The present work has demonstrated that atomic layer deposition, characterized by short reaction time, no consumption of organic solvents and high functional group density, is a cost-effective and eco-friendly approach for preparation of silica based palladium scarvengers.