A tool for replacing an escalator drive shaft comprises a first tool and a second tool. One side of the first tool is adapted to be assembled on an original shaft adapter, and the other side of the first tool is adapted to be assembled on a new shaft adapter. The second tool is adapted to be assembled on the first tool. A central axis of the first tool coincides with a central axis of the original shaft adapter, a central axis of the second tool coincides with the central axis of the first tool, and the central axis of the first tool coincides with a central axis of the new shaft adapter. A positioning reference of the original drive shaft is accurately transferred to the new drive shaft by the first and second tools, so that the new drive shaft may be accurately assembled to the position of the original drive shaft with respect to the truss after replacement.