SnS/graphene nanocomposite has been prepared through a simple one-step and in situ method using thiourea as the sulfur source and reducing agent. The formation of SnS nanoparticles and the reduction of graphene oxide occur simultaneously during the hydrothermal process. The SnS nanoparticles are dispersed uniformly on graphene nanosheets and the SnS/graphene nanocomposite exhibits a relatively high reversible capacity and good cycling stability. The excellent electrochemical performance can be attributed to graphene, which prevents the agglomeration of SnS nanoparticles and improves the electronic conductivity of overall nanocomposite. The SnS/graphene nanocomposite combines the advantages of the good cycling stability of graphene and the high capacity of SnS nanoparticles.