The invention relates to an automatic assembly device for a semi-product split flap board of a lithium battery cover plate, which comprises a split flap board delivery mechanism arranged on a rack and a drive motor, wherein the rack is also provided with a rivet vibration feed mechanism, a rivet installing mechanism, an automatic riveting mechanism and an electrode plate delivery mechanism in turn; and the split flap board delivery mechanism uses a transferring screw rod, and the screw threads of the transferring screw rod are matched with regular tooth shaped notches preset on the edge of the semi-product split flap board. The invention is characterized in that the invention uses the screw threads of the transferring screw rod to be matched with the regular tooth shaped notches preset on the edge of the semi-product split flap board, so as to lead the shift to be correct when the split flap board is delivered; various mechanisms on the rack automatically work in turn, which can achieve automatic installation of the rivets and the electrodes plate riveting on the semi-product split flap board injected with insulating strips; the arrangement of various mechanisms of the whole device is reliable, thereby greatly improving production efficiency and assembly precision, saving labor, reducing failure rate of the product, obviously reducing cost and having better production safety.