SnS2/SnO2 composites were prepared in a microwave-assisted reaction of a mixture solution of SnCl4 and l-cysteine and were characterised by XRD, TEM, SEM and EDX. The influence of the mole ratio of SnCl4 to l-cysteine (l-cys) on the sample was investigated. It was found that using a microwave method, SnS2/SnO2 composites were formed, and SnS2/SnO2 nanoparticles were obtained when the mole ratio of SnCl4 to l-cysteine was 1:2. With higher contents of l-cys, when the mole ratio of SnCl4 to l-cys was 1:4, the products were nanosheets instead of nanoparticles. Electrochemical tests demonstrated that the SnS2/SnO2 composites with layer structure exhibited high reversible capacities and good cycling performances when used as anode materials of Li-ion batteries. When the mole ratio of SnCl4 to l-cys was 1:6, the initial reversible capacity of products was 593mAh/g, and the retention capacity that was maintained was over 88%. Besides, the retention capacity of products was still excellent at high current charge/discharge.