The sodium vanadate (Na0.76V6O15) nanobelts have been successfully synthesized via a facile hydrothermal reaction followed by annealing. The ultra-long nanobelts have a length ranging from several micrometers to several dozens of micrometers. As cathode materials for lithium-ion batteries, the Na0.76V6O15 nanobelts exhibit high discharge capacity, excellent cyclic stability and good rate capability. High discharge capacity of 248 and 214 mA h g−1 can be obtained at the current density of 300 and 500 mA g−1, respectively. Meanwhile, it maintains a stable capacity of 113 mA h g−1 after 200 cycles at a high current density of 2000 mA g−1 with no capacity decay. The superior electrochemical performances may be attributed to the novel nanobelts structure and excellent structural stability of Na0.76V6O15.