A series of composite SnO materials were prepared by mixing SnO powder with reducing agents and heating at different temperatures for different periods under argon atmosphere. It was found that alpha-SnO with its tetragonal structure could transform into the beta-Sn phase or orthorhombic SnO depending on treatment conditions. The electrochemical behaviors of these materials used as an anode active material in lithium rechargeable batteries was investigated. It was found that excessive amounts of reducing agents, especially in the case of carbon black, may provide a good dispersion environment for SnO which is similar to the case of amorphous tin composite oxides (TCO). The presence of beta-Sn or orthorhombic SnO is not beneficial to the cycling performance, although a large ratio of beta-sn in the starting anode material can decrease the capacity loss during the first cycle. Superfine SnO material was also prepared by decomposing SnC2O4 which was synthesized by a sol-gel method. Its cyclic performance was improved significantly.