The invention provides a method for installing a tail wedge, and relates to the technical field of ships and ocean structures. The method comprises the steps that a suitable type of tail wedge is selected according to the navigation state of a ship; a tail wedge mounting part is arranged at the bottom side of a hull stern, and the suitable type of tail wedge is conveyed to the tail wedge mountingpart through a tail wedge conveying device; the tail wedge is detachably mounted to the tail wedge mounting part. The method solves the technical problem that a ship cannot always maintain the best energy-saving effect at different drafts and navigation states of different speeds in the prior art.