The invention relates to a device and method for preparing graphene oxide (GO) by an electrolytic oxidation method, and belongs to the field of large-scale production of the graphene oxide.Existing problems in existing preparation methods of the graphene oxide are solved. The device includes a GO reaction system, a GO rapid recovery system, an electrolyte cooling and recovery system and other corecomponents. According to the device, sulfuric acid is used as an electrolyte, and graphite paper is used as aproduction raw material. First, a graphite raw materialiselectrolytically intercalated toincrease graphite layer spacing and improve oxidation efficiency. Second, intercalated graphite is electrolytically oxidized under high voltage, the surface of a graphemematerial is connected with a large number of oxygen-containing groups, and finally the GO is obtained. The generated GO is quickly separated and recycled, and the electrolyte is also recovered and recycled synchronously. Accordingto the GOgeneration device, any heavy metal ion and other harmful substance discharging is not conducted, and amplification design with varying degrees is conducted according to a production scale.