Effect of TiO₂ nanoparticles on transport of Cu in various soils was studied in a leaching experiment. It was found that TiO₂-nanoparticle-colloids-associated Cu was the sole and main form transporting in sand and sandy-loam soils relatively low in soil organic matter and high in cation exchange capacity, respectively. The presence of TiO₂ nanoparticles actually increased the movability of Cu by 8 432 and 32 times in sand and sandy-loam soils, respectively. However, this enhanced phenomenon was significantly reduced in silt-sandy-loam and loam soils. In silt-sandy-loam soil, only 1.35% of Cu was transported in TiO₂-nanoparticle-associated form. In loam soil, soluble Cu was the sole form in transportation and TiO₂ nanoparticles were no longer the carrier. During the transport through soils, the previously adsorbed Cu on TiO₂ nanoparticles were effectively stripped off and extent of the stripping depended on soil properties. Soil organic matter demonstrated a strong tendency to get into chelation with Cu, therefore soil organic matter is an important factor that determines desorption of Cu from TiO₂ nanoparticles. The higher the content of soil organic matter in the soil, the easier for it to compete for Cu adsorption with TiO₂ nanoparticles and the higher the Cu desorption rate in the soil.