Hierarchical-structured SnO-SnO2 composite powders and SnO nanoplates with some SnO2 nanorods are prepared by one-pot spray pyrolysis. Dicyandiamide dissolved in the spray solution plays a key role in the preparation of the hierarchical-structured SnO-SnO2 composite powder and SnO nanoplates. The hierarchical-structured SnO-SnO2 composite powders, in which the SnO nanoplates are trapped in the porous SnO2 nanosphere, are prepared by spray pyrolysis at 800 °C. Sufficient conversion of the porous SnO2 nanospheres to SnO at 900 °C results in aggregation-free SnO2 nanoplates. SnO2 nanorods with a spherical nanodroplet at the tip are formed by Ostwald ripening. The hierarchical-structured SnO-SnO2 composite powder having high structural stability during repeated lithium alloying and dealloying reactions, shows superior discharge capacities and rate performances for lithium-ion storage compared to those of the dense-structured SnO2 powders. The discharge capacities of the hierarchical-structured SnO-SnO2 composite powders, SnO nanoplates with SnO2 nanorods, and dense-structured SnO2 powders at a current density of 1 A g−1 for the 300th cycle are 561, 504, and 416 mA h g−1, respectively. The SnO nanoplates with SnO2 nanorods and hierarchical-structured SnO-SnO2 powders deliver high reversible discharge capacities of 433 and 379 mA h g−1 at an extremely high current density of 10 A g−1, respectively.