The invention relates to a lithium battery charging system which belongs to the technical field of battery cell manufacturing. The lithium battery charging system comprises two parallel spaced conveyor rollers used for conveying a cell group, anda first and a second charging mechanisms successively arranged across the conveyor rollers, wherein each of the first and the second charging mechanisms is provided with a frame arranged across the conveyor rollers, probes installed at the top of the frame, and lifting components which are arranged below the frame and correspond to the positions of the probes, the lifting components are arranged between the two conveyor rollers, and one end of each lifting component is provided with a stopper. When the cell group is blocked by the stoppers and lifted by the lifting components, the probes and corresponding pole lugs of the cell group are correspondingly compacted, the probes on the first charging mechanism are connected in series and then connected to a series charger, and the probes on the second charging mechanism are connected in parallel and then connected to a parallel charger. When the lithium battery charging system is used, a battery pack can be automatically filled with the voltage when being not full, and the consistency of product parameters can be guaranteed.