The invention relates to a document automatic access device and a control method, which belong to the technical field of automation. The device comprises a support frame, a control panel, a bottom board, a document holder, a guide rail, a driving belt A, a document box, an x-axis movable mechanism, a y-axis movable mechanism and a z-axis movable mechanism. The control method of the device comprises the following steps: (1) determining an initialization parameter; (2) determining whether to debug or run according to a parameter of the position at which the document is; (3) if running, determining picking and placing; (4) if debugging, performing X-axis, Y-axis and Z-axis inching movements of a mechanical arm respectively; (5) determining the moving mode of the document holder; and (6) returning the mechanical arm to an original point. The device and the method have the advantages that the document intelligent intensive access can be achieved through a document storage intensive mechanism, an access mechanical arm and an automatic control system, more storages and error-free high-efficiency access of documents are not needed to be set according to categories, and the technique can be widely applied in similar industries, supermarkets and other public places.