Rechargeable multivalent ion batteries have attracted significant technical and scientific interests, especially aqueous zinc ion batteries, due to their low cost and high safety.1 Layered V3O7·H2O is a promising material due to easy intercalation of doubly charged Zn2+ ions. This is due to the special structure with extended hydrogen bonding between VO6 octahedrons and VO5 trigonal bipyramids.2 In addition, the mixed oxidation state of vanadium (IV and V) can help improve the electric conductivity. With the addition of reduced graphene oxide, rGO, the active materials obtain high electrochemical stability. Herein, we have synthesized V3O7·H2O nanowires/reduced graphene oxide composite by a microwave method through controlling pH by a nonoxidizing acid and have thoroughly investigated the reaction mechanisms of the synthesis. A composite used as the cathode of the zinc-ion battery can deliver a high specific capacity of 385.7 mAh g-1 at a current density of 4 A g-1. Impressively, the capacity retention after 1000 cycles is up to 96%. This excellent performance suggests that vanadium oxide and rGO composite may be a good cathode candidate for an aqueous zinc ion battery.