Double pile casing construction method for controlling perpendicularity

The invention relates to the technical field of cast-in-place pile construction and discloses a double pile casing construction method for controlling the perpendicularity. The double pile casing construction method comprises the following construction steps of (1) measuring and locating a pile position on situ, and arranging four crossed locating points; (2) vertically submerging an outer pile casing within an encirclement ring formed by the four locating points; and (3) respectively convexly arranging a locating plate on a position, aligning to each locating point, on the inner wall of the outer pile casing; and vertically submerging an inner pile casing in the outer pile casing, and respectively enabling the outer ends of the four locating plates to support against the outer surface of the inner pile casing. The outer pile casing and the inner pile casing simultaneously act, so that the frictional resistances of the outer pile casing and the inner pile casing in the submerging and withdrawing processes are reduced; the inner pile casing and the outer pile casing can be utilized repeatedly, so that the construction cost is reduced; the inner pile casing is limited and located by using the four locating plates to ensure that the central point of the inner pile casing is coincided with the central point of a pile hole, so that the inner pile casing is accurately located, and the pile forming quality is effectively ensured.