MoO2/C nanocomposite has been prepared by simultaneously reducing as-prepared MoO3 nanosheets and introducing an amorphous carbon matrix in the combination of facile hydrothermal and post-annealing processes. MoO2 nanoparticles are uniformly embedded in the carbon framework, resulting in porous nanostructured MoO2/C composite material. The MoO2/C electrodes exhibit varied electrochemical working mechanisms for sodium ion storage that is dependent on charge/discharge rates. At low charge/discharge rate conditions, MoO2/C nanocomposite shows dominant battery performances for sodium ion storage involving reversible conversion reaction of MoO2. The MoO2/C anode material can deliver high initial charge capacity of 557.2mAh/g at 0.1C (1C =600mA/g), along with good cycling stability in comparison with bare MoO2 material. At high rate situations, cyclic voltammetric (CV) results indicate distinct pseudocapacitive behaviors of MoO2/C materials when the scanning rate is higher than 0.5mV/s. Specific capacitances of 123.25, 85.47 and 49.90F/g can be obtained from CV measurements conducted at 1, 2 and 5mV/s, respectively. These electrochemical performances illustrate remarkable capabilities of MoO2/C nanocomposite as anode material for sodium ion storage involving varied conversion reactions and pseudocapacitive sodiation/desodiation reactions depending on charge/discharge rates.