A graphene-supported CeSnS2 (CeSnS2/graphene) nanocomposite has been synthesized via a hydrothermal route. Structure, morphology, and electrochemical properties of the composites were studied by means of XRD, SEM, TEM, Raman, XPS, TGA, and electrochemical measurements. The CeSnS2 crystal particles with a flower-like structure were distributed on the graphene sheets (GNS). The particle sizes of each petal are in the range 50–100 nm with clear lattice fringes. The atomic ratio of Sn, S, Ce, C, and O is estimated to be 1:2:0.05:3.11:0.64 and the content of CeSnS2 composite is 80 wt.% in the as-synthesized sample. The CeSnS2/graphene composite exhibits high initial discharge capacity (1638.3 mAh/g at 0.5 C), high capacity retention (707 mAh/g at 0.5 C after 50 cycles), and good rate capability due to the synergy effect between CeSnS2 nanoparticles and graphene nanosheets. The superior performance is ascribed to the presence of graphene keeping the structure stable.