Single-crystalline SnO2 nanocones with an average 1.0 mu m in length and 100-500 nm in root size and their self-assembly morphologies were obtained through a solvothermal process in the presence of poly(acrylic acid). X-ray diffraction, electron microscopy, Raman scattering spectra, and infrared (IR) spectra were used to characterize the nanocones. The as-synthesized SnO2 nanocones with the typical rutile phase exhibit preferential growth along the [001] direction and high chemical stability. The proposed mechanism for the formation of SnO2 nanocones and the further self-assembly into hollow sphere-like superstructure is discussed.