Li2MnSiO4/C composite is prepared by sol–gel method with Mn3O4 nanoparticle, and its carbon content, structure, and morphology are characterized. The results show that Li2MnSiO4/C exhibits pure phase with orthorhombic structure and the size of Li2MnSiO4 (20–30 nm) is smaller than Mn3O4 nanoparticle. As the cathode material of lithium-ion battery, Li2MnSiO4/C delivers an initial discharge capacity of about 240 mAh g−1 at the current density of 8 mA g−1, corresponding to 1.44 mol of Li+ per formula unit. The cycle performance of Li2MnSiO4/C at different current densities from 8 mA g−1–320 mA g−1 is studied, and it is found that the capacity retention is improved with the increasing of current density. Basing on the results of ex-situ X-ray diffraction measurement, it is inferred that low degree of irreversible distortion for Li2MnSiO4 may result in the improved capacity retention at high current density.