An impregnation–calcination method based on the thermal decomposition of stannous sulfate is developed to prepare carbon cryogel-tin oxide nanocomposites with less impurity for anode materials of lithium-ion batteries. Structural characterization reveals that the tin oxide nanoparticles, arising from the decomposition of stannous sulfate, are homogeneously distributed inside the pores of carbon cryogels. The detail results demonstrate that carbon cryogels with large specific surface area, large porosity, and small mesopores are beneficial to the deposition of tin oxide nanoparticles. As a result, carbon cryogel–tin oxide nanocomposites with optimized structures show a discharge capacity of 590mAh/g after 50 cycles, much higher than that of either carbon cryogels, pure tin oxides or their mechanical mixture. The superior electrochemical properties of carbon cryogel–tin oxide nanocomposites could be attributed to their novel microstructures and the synergistic effects between carbon cryogels and tin oxide.