The invention relates to an electric vehicle chassis battery charging and replacing device. The electric vehicle chassis battery charging and replacing device comprises a ground slide guide rail, a mechanical arm, a battery box and a battery frame, wherein the mechanical arm is arranged on the ground slide guide rail; the battery frame is used for placing the battery box; a non-standard clamp used for clamping the battery box is arranged on the mechanical arm; the battery frame comprises a frame body, a charging layer, a working layer and a stored to-be-charged layer; each of the charging layer, the working layer and the stored to-be-charged layer is provided with a lifting table, a moveable guide rail and a tray which are arranged on the frame body; a pressure sensor is arranged on each tray; each lifting table is connected with the frame body through each lifting guide rail; the moveable guide rail is arranged on each lifting table; each tray is arranged on each moveable guide rail of each lifting table. The electric vehicle chassis battery charging and replacing device is convenient and quick in work, clear in labor division, flexible in clamping, precise in positioning, and stable and reliable in the whole working process, the requirement of quickly replacing the battery of a large-mass electric vehicle is better met, the battery charging and replacing efficiency is greatly improved, and the problems of low battery charging and replacing efficiency and the like of the electric vehicle are solved.