Mono-dispersed SnO2 1D nanostructures of different diameters and SnO2 1D nanostructures with graded diameters have been fabricated by modulating oxygen partial pressure in chemical vapor deposition method, in which Sn powder and oxygen gas were used as the source materials. Experimental results indicate that the diameters and the band gap of SnO2 1D nanostructures depend much on the oxygen partial pressure in the growth chamber. When the oxygen partial pressure is increased or decreased during the growth process, the diameter of SnO2 nanowire increases or decreases, while the band gap decreases or increases due to oxygen vacancies and tin interstitial atoms, correspondingly. Furthermore, the change of oxygen partial pressure can also induce change in growth directions of SnO2 1D nanostructures. The growth mechanism of SnO2 nanowires under different growth conditions is also discussed. (C) 2009 Elsevier B.V. All rights reserved.