The invention discloses a macro preparation device and method of carboxyl functionalized graphene and belongs to the technical field of preparation of graphene. The macro preparation device comprisesa first dispersion kettle, an activation reactor, a first filtering and washing tower, a second dispersion kettle, a reaction kettle, a second filtering and washing tower, a third dispersion kettle, adrying tower, a first storage tank and a second storage tank, wherein the first dispersion kettle, the activation reactor, the first filtering and washing tower, the second dispersion kettle, the reaction kettle, the second filtering and washing tower, the third dispersion kettle and the drying tower are connected in sequence; the first filtering and washing tower, the first storage tank and thefirst dispersion kettle are connected in sequence; the second filtering and washing tower, the second storage tank and the second dispersion kettle are connected in sequence. The macro preparation device and method of the carboxyl functionalized graphene, disclosed by the invention, have the advantages of simple and compact structure, reasonable design, high continuous degree and less equipment investment; the carboxyl functionalized graphene can be efficiently prepared and the production cost is reduced.