The invention provides an old saggar retreatment method. The old saggar retreatment method comprises the steps that firstly, saggar grinding equipment is used for grinding the inner bottom face of anold saggar; and secondly, the inner bottom face of the ground old saggar is coated with a nickel cobalt lithium manganate solution or a lithium cobalt oxide solution. According to the provided old saggar retreatment method, the service life of the saggar is prolonged, and accordingly, the manufacturing cost of lithium battery positive electrode materials is reduced.