Silver vanadium oxide (Ag1.2V3O8) has been successfully synthesized by a facile solid-state reaction between AgNO3 and sol–gel prepared VOC2O4. The morphology and phase of the calcinations products are largely temperature-dependent. The morphologies of the calcinations products evolutes from nanorods to nanobelts and higher purity can be obtained with the raise of temperatures. Nanobelts with a thickness around 200 nm can be obtained at 450 °C. The as-synthesized Ag1.2V3O8 nanobelts are of single crystal. As a cathode material for rechargeable lithium ion batteries, the Ag1.2V3O8 nanobelts exhibit good cyclic stability and high-rate capability. A stable specific discharge capacities of 215, 198, and 174 mA h g−1 can be delivered at the current densities of 50, 100 and 200 mA g−1, respectively. The superior performances are attributed to the good reversibility of electrochemically formed LiV3O8 and improved conductivity by in-situ formed Ag phase.