In this paper, we report on the preparation of Li2FeSiO4, sintered Li2FeSiO4, and Li2FeSiO4-C composite with spindle-like morphologies and their application as cathode materials of lithium-ion batteries. Spindle-like Li2FeSiO4 was synthesized by a facile hydrothermal method with (NH4)2Fe(SO4)2 as the iron source. The spindle-like Li2FeSiO4 was sintered at 600 °C for 6 h in Ar atmosphere. Li2FeSiO4-C composite was obtained by the hydrothermal treatment of spindle-like Li2FeSiO4 in glucose solution at 190 C for 3 h. Electrochemical measurements show that after carbon coating, the electrode performances such as discharge capacity and high-rate capability are greatly enhanced. In particular, Li2FeSiO4-C with carbon content of 7.21 wt% delivers the discharge capacities of 160.9 mAh·g−1 at room temperature and 213 mAh·g−1 at 45 °C (0.1 C), revealing the potential application in lithium-ion batteries.