The Sn4+ doped anatase TiO2 nanocrystals with various amounts of dopant Sn4+ ions were prepared from peroxo-metal-complex precursor by solvothermal method and characterized by XRD, TEM, HRTEM, XPS, ICP-AES and UV-vis spectrophotometer. The experimental results indicated that the dopant Sn4+ substituted Ti4+ in the lattice of TiO2, which reflected in the lattice expansion in both a- and c-direction and change of the binding energy. All the Sn4+ doped TiO2 nanocrystal samples appeared to be anatase evenly with dopant level up to 10 mol%. The effect of dopant Sn4+ ions and reaction solvents on physicochemical properties of the obtained Sn4+ doped anatase TiO2 nanocrystals had been discussed. In addition, the growth mechanism and microstructure evolution of Sn4+ doped anatase TiO2 nanocrystals had been suggested. The photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals was tested by the degradation of phenol. Compared with the undoped TiO2 sample, the enhanced photocatalytic activity of the Sn4+ doped anatase TiO2 nanocrystals could be attributed to modification of the optical properties and surface state by doping the optimum concentration of Sn4+. ions. (c) 2011 Elsevier B.V. All rights reserved.