Cyanide wastewater is a very highly toxic substance. In this study, a kind of silicon-based nano-TiO₂ material by turning pore size accurately is prepared to treat cyanide wastewater. The materials are characterized by XRD, TG analysis, N₂ adsorption/desorption test, UVAS analysis and TEM. Results show that adding NaCl to the synthesis of silica supports can change the size of pores. It emerges that pore size can affect the catalytic performance of the material. Catalytic experiments confirm that cyanide has the best catalytic effect when it has a pore size of 16.47 nm. UVAS spectrum demonstrate that the cyanide has been broken down rather than adsorbed onto the material.