The invention discloses a pre-stressed carbon fiber tensioning and anchoring device for beam fatigue resistance. The pre-stressed carbon fiber tensioning and anchoring device comprises a carbon fiberflexible tensioning device, a wedge-shaped block, an anchoring clamp A and an anchoring clamp B. The anchoring clamp A and the anchoring clamp B are arranged on the lower surface of a to-be-reinforcedbeam at intervals in the axial direction of the to-be-reinforced beam, the two ends of the carbon fiber flexible tensioning device are fixed to the anchoring clamp A and the anchoring clamp B respectively, the wedge-shaped block is located between the anchoring clamp A and the anchoring clamp B, and the two ends of the wedge-shaped block abut against the upper end surface of the carbon fiber flexible tensioning device and the lower surface of the beam to be reinforced respectively. The carbon fiber flexible tensioning device is tensioned through the synergistic effect of end tensioning devices and a central tensioning device, the tensile elastic deformation quantity of the carbon fiber flexible tensioning device can be 10%-30%, the end tensioning devices and the central tensioning devicecan be repeatedly used for multiple times, and the engineering cost is effectively controlled while the technical effect is achieved.