A method for replacing an escalator drive shaft, comprising the step: S101: removing an original drive shaft and an original shaft collar from a truss of an escalator, and retaining an original shaft adapter matching with the original shaft collar on the truss; and characterized at least by the further steps: S102: providing a first tool, and assembling one side of the first tool on the original shaft adapter, wherein the first tool and the original shaft adapter have first positioning features (310a', 12a) which fit with each other, so that a central axis of the first tool assembled on the original shaft adapter coincides with a central axis of the original shaft adapter; S103: providing a second tool, assembling the second tool on the first tool, wherein the first tool and the second tool have second positioning features (10a, 20a) which fit with each other, so that a central axis of the second tool assembled on the first tool coincides with the central axis of the first tool; S104: fixing the second tool on the truss; S105: removing the first tool and the original shaft adapter from the truss; S106: assembling the other side of the first tool on a new shaft adapter, wherein the first tool and the new shaft adapter have third positioning features (300a, 14a) which fit with each other, so that the central axis of the first tool assembled on the new shaft adapter coincides with the central axis of the new shaft adapter; S107: assembling the first tool and the new shaft adapter into the second tool, wherein the first tool and the second tool matching with each other by the second positioning features (10a, 20a), so that the central axis of the new shaft adapter coincides with the central axis of the second tool; S108: fixing the new shaft adapter to the truss; S109: removing the first tool and the second tool from the truss; S110: assembling a new drive shaft and a new shaft collar onto the new shaft adapter. S102: providing a first tool, and assembling one side of the first tool on the original shaft adapter, wherein the first tool and the original shaft adapter have first positioning features (310a', 12a) which fit with each other, so that a central axis of the first tool assembled on the original shaft adapter coincides with a central axis of the original shaft adapter; S103: providing a second tool, assembling the second tool on the first tool, wherein the first tool and the second tool have second positioning features (10a, 20a) which fit with each other, so that a central axis of the second tool assembled on the first tool coincides with the central axis of the first tool; S104: fixing the second tool on the truss; S105: removing the first tool and the original shaft adapter from the truss; S106: assembling the other side of the first tool on a new shaft adapter, wherein the first tool and the new shaft adapter have third positioning features (300a, 14a) which fit with each other, so that the central axis of the first tool assembled on the new shaft adapter coincides with the central axis of the new shaft adapter; S107: assembling the first tool and the new shaft adapter into the second tool, wherein the first tool and the second tool matching with each other by the second positioning features (10a, 20a), so that the central axis of the new shaft adapter coincides with the central axis of the second tool; S108: fixing the new shaft adapter to the truss; S109: removing the first tool and the second tool from the truss; S110: assembling a new drive shaft and a new shaft collar onto the new shaft adapter.