The invention provides an adaptive elongated anchor rod, and belongs to the technical field of engineering construction. The adaptive elongated anchor rod comprises sectional outer pipes, two adjacentouter pipes are abutted, an elongated rod is arranged at a connector of the two adjacent outer pipes, elastic limit projections are arranged on the outer sides of the side walls of two ends of the elongated rod, and projection limit holes are correspondingly formed in the two adjacent outer pipes at the connector. The elongated anchor rod solves the problems that the length of an existing anchorrod is fixed and cannot be freely changed according to use conditions, the radius of a crushing area easily exceed the length of the anchor rod, and supporting effects are sharply reduced.