The invention relates to a seamless-connection baking starting method for a large prebaked aluminum electrolysis cell. In the baking process of the aluminum electrolysis cell, the point of the lowest cell voltage serves as an electrode lifting opportunity; in the electrode lifting process, unmelted materials are transferred to the area of melted materials, so that material melting is accelerated; after the materials are melted, fishing of carbon slag is started on both sides, and then a cell control machine of the electrolysis cell is switched on for automatic feeding; and after aluminum filling, start-up of the electrolysis cell is completed. Through the method, the defects of non-uniform anode current distribution and non-uniform lining temperature rise in the baking process of the aluminum electrolysis cell can be effectively overcome, thermal shock to a cathode carbon block is reduced, and the method is beneficial for prolonging the service life of the electrolysis cell.