Electrode materials of SnO2.xH2O are synthesized at low temperature by hydrolysis precipitation process. After calcination at various temperatures, the as-prepared powders are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA). XRD patterns confirm the structure of SnO2.xH2O powders to be tetragonal. TEM images reveal the morphology of the as-prepared SnO2?xH2O powders, and TGA shows the water content in SnO2.xH2O, which decreases as the calcination temperature increases. Electrochemical tests, such as cyclic voltammetry (CV), cycling and chronopotentiometry test are also performed to study the supercapacitor behavior of the calcined SnO2?xH2O powders. Cyclic voltammetric results indicate that SnO2?xH2O powders calcined at 200℃ has a maximum specific capacitance of 36.1 F g-1 at the scan rate of 5 mV s-1 in 0.5 M H2SO4 aqueous electrolyte. Cycling test on the same sample also shows excellent long-term cyclic stability, which has lost less than 2 % of the total specific capacitance after 2000 cycles. These results indicate that SnO2.xH2O powders prepared from hydrolysis precipitation process are excellent candidates as electrode materials towards the applications of supercapacitor.