【Abstract】 In this paper, we report our research on morphologically selective synthesis of nanocrystalline SnO 2 by the combination of hydrothermal preparation and calcinated process. We firstly prepared SnO 2 nanocrystals by the hydrothermal method at 140 ℃ for 3 h, using SnCl 4 as the reactant. With the initial pH of 1.8 or 1.34, we prepared uniform and well dispersed SnO 2(tetragonal) nanocrystals, with similar size of about 3 nm, as determined by TEM. However, after being calcinated at 500 ℃ for 2 h, specimen 1 prepared at pH=1.8 showed the rod like shape with an average size of 5 nm×20 nm, while the other one(specimen 2) prepaed at pH=1.34 showed a granular shape with an average size of 10 nm. XRD experiments showed that specimen 1 had a new diffraction peak after calcination, which was contributed by the (023) face of orthorhombic SnO 2. The experiment results indicated that the morpholgy of SnO 2 nanocrystals after calcination was closely related to the initial acidity of the reaction solution, possibly due to the difference in surface properties, e.g. the difference in crystalline faces exposed to the surface of particals, under different hydrothermal conditions. [WT5HZ]更多还原