NH4V3O8/carbon nanotubes (CNTs) composites are synthesized by one-step hydrothermal method. All the samples show the flake-like morphology with the width of up to 5μm and thickness of 500nm and the CNTs are clearly observed on the surface of modified NH4V3O8. It is found that incorporation of 0.5wt% CNTs into NH4V3O8 could greatly improve its discharge capacity and cycling stability. It delivers a maximum discharge capacity of 358.7mAhg−1 at 30mAg−1, 55mAhg−1 larger than that of the pristine one. At 150mAg−1, the composite shows 226.2mAhg−1 discharge capacity with excellent capacity retention of 97% after 100 cycles. The much improved electrochemical performance of NH4V3O8 is attributed to incorporation of CNTs, which facilitates the interface charge transfer and Li+ diffusion.