The invention provides a novel open hole anchor. A slab bridge assembly is adopted as an anchoring element, the contact area with the hole wall is increased, anchoring force is ensured, and the hole wall is not damaged. A damping foldable spring is adopted for reducing vibration of a pipe column, and the current effective anchoring time is prolonged. Through a rotary lock sleeve, a one-way lock ring, a sliding bolt and a tension spring, switching of the multiple states of anchoring fixation, anchoring keeping and anchoring relief can be achieved conveniently during one time of hole descending, the flexibility of usage of the open hole anchor is ensured, and thus builders can cope with various construction requirements and unforeseen circumstances flexibly. The rotary lock sleeve can be located according to the size of a shaft, and the reliability of every time of anchoring fixation is ensured.