Abstract: Because of the non-degradability of heavy metal ions and their serious injury to the human body, removal of heavy metal ions in industrial waste water has become very urgent. The adsorption method is widely used due to simple operation, low cost, and less secondary pollution. Mesoporous SiO₂ with a high specific surface, good thermal stability and mechanical property becomes a good metal adsorbent. In this study, mesoporous SiO₂ functionalized by iminodiacetic acid (IDA) (mSiO₂-IDA) was prepared to explore the adsorption of Cu²⁺ and Cd²⁺. The prepared mSiO₂-IDA was analyzed and characterized by elemental analysis (EA) and FT-IR spectroscopy, which confirmed that IDA was successfully grafted on the surface of mSiO₂. The effect of solution pH, initial metal ion concentration and time on the adsorption of Cu²⁺ and Cd²⁺ onto mSiO₂-IDA was studied. The capacity of adsorption changed with the increase of pH, the maximum adsorption appeared at pH=5. Then the kinetics of adsorption at pH=5 was studied. The adsorption rates and capacity reached the maximum within 30 min. Besides, the adsorption capacity of mSiO₂-IDA at different initial concentrations was studied. Adsorption capacity increased with the increase of initial concentrations and the highest adsorption capacities were 49.0 mg/g and 43.5 mg/g for Cu²⁺ and Cd²⁺ respectively. It was concluded that the removal efficiency of Cu²⁺ and Cd²⁺ achieved 97.9% and 92.1% within 30 min respectively at pH=5 by 2 g/L mSiO₂-IDA. Meanwhile, in order to determine the adsorption rate constant and explore adsorption mechanism of mSiO₂-IDA to Cu²⁺ and Cd²⁺, their data of adsorption kinetics were fitted. The adsorption behavior was better described by pseudo-second-order equation, and the adsorption isotherm followed Langmuir one. As revealed by X-ray photoelectron spectroscopy (XPS), the adsorption mechanisms of Cu²⁺ and Cd²⁺ onto mSiO₂-IDA are different. mSiO₂-IDA showed a good adsorption performance to Cu²⁺ and Cd²⁺.