The invention provides an online slitting device for RFID tag production. The online slitting device at least comprises a rack and a panel, wherein the panel is vertically and fixedly installed on the rack; an idler roll component, a swing roll component, a rubber roll component, a drive roll component, a tool rest slitting component and a receiving roll component are horizontally installed on the panel; an RFID tag substrate to be slit sequentially passes through the abovementioned components, is slit by the tool rest slitting component and then is finally wound by the receiving roll component. The device provided by the invention improves the prior art and solves problems in the prior art; and the device is better in online slitting effect, and simpler and more reliable in structure, a user can much conveniently operate, the production efficiency can be greatly increased, the cost is reduced, and an important role is played in energy conservation, environment protection and economic benefits.