Porous SnO2 nanostructures with controlled shapes were synthesized by a facile morphologi-cally conserved transformation from SnC2O4 precursor approach. Well-defined SnC2O4 nanostructures can be obtained through a solution-based precipitation process at ambient conditions without any surfactant. The formation mechanism of such microstructures was tentatively proposed on the basis of intrinsic crystal struc-ture and the reaction conditions. We found that the morphologies of precursor were well maintained while numerous pores were formed during the annealing process. The combined techniques of X-ray diffraction, ni-trogen absorption–desorption, field emission scanning electron microscopy, and (high-resolution) transmission electron microscopy were used to characterize the as-prepared SnO2 products. Moreover, cyclic voltammetry (CV) study shows that the shape of CV presents a current response like roughly rectangular mirror images with respect to the zero-current line without obvious redox peaks, which indicating an ideal capacitive behavior of the SnO2 electrodes. The photoluminescence (PL) spectrum study suggests that the as-obtained porous SnO2 nanostructures might have a large number of defects, vacancies of oxygen, and local lattice disorder at the interface, interior and exterior surfaces.