New kinds of onion-like hollowcarbon nanoparticles (OC) with amean diameter of 40 nmwere synthesized by the pyrolysis of carbon black at 1000 ℃ in a nitrogen atmosphere using ferric nitrate as the catalyst precursor. By impregnating with a SnCl2/ethanol solution and oxidation in air at 350 ℃, OC doped SnO2 nanoparticle composites were obtained. Then, by rinsing with hydrochloric acid to remove the coated SnO2 nanoparticles, OC-encapsulated SnO2 nanoparticle composites were prepared. The morphologies and structures of OC and the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The content of SnO2 in the composite was measured by thermogravimetric analysis (TGA). The electrochemical properties of the composites as anode materials for lithium-ion batteries were evaluated by galvanostatical method and cyclic voltammetry (CV). We found that after acid treatment the sample possessed a reversible capacity of 446 mAh·g-1 after 50 cycles and excellent cycle stability. This indicates that OC is a suitable matrix to buffer against volume expansion and to prevent the agglomeration of SnO2 nanoparticles.