Porous SnO2 nanocrystalline thin films were successfully electrodeposited from an oxygen-saturated acid aqueous solution of SnCl2 containing different concentrations of butyl-rhodamine B(BRhB)at 70 ℃.BRhB with substitute of amidocyanogen can be dissolved in the acid deposition solution,where HC1 was added to suppress hydrolysis of SnCl2.So it was used as a structure-directing agent to promote the crystal growth of SnO2.The formed porous morphology and tetragonal rutile crystalline structure of the electrodeposited thin films were controlled by the addition of BRhB with different amounts.