In order to improve the rate performance of MoO3, a novel MoO3 nanobelt with tiny grains on surface (named as d-MoO3) is fabricated via one-step facile hydrothermal method with citric acid adding, in which citric acid (CA) serves as a weak reductant as well as surface modification agent. When tested as an anode in LIBs, d-MoO3 displays an improved discharge capacity of 787 mAh.g(-1) at 0.1 A g(-1) over 100 cycles with capacity retention of similar to 91% while MoO3 decays to 50 mAh.g(-1) in the 100th cycle. Notably, d-MoO3 delivers enhanced rate capability (536 and 370 mAh.g(-1) at high rates of 5 and 10 A g(-1) respectively). We consider these excellent electrochemical properties of d-MoO3 electrode are associated with the tiny grains on MoO3 surface, which effectively maintains the electrodes structural integrity. Even though d-MoO3 nanobelt suffers from a degree of in-situ pulverization after several cycles, these pulverized active particles can still maintain stable electrochemical contact and are highly exposed to electrolyte, realizing ultrahigh e(-)/Li+ diffusion kinetics. In addition, part extrinsic pseudo capacitance contribution to the Li+ storage also explains the high-rate performance. Combining all these merits, d-MoO3 is potentially a high-energy, high-power and well-stable anode material for Li ion batteries (LIBs).