Experimental research was performed on the flexural strength capacity of RC beams subjected to thermal shock after heated to 500 °C and 700 °C for three hours, and then quickly cooled using a CO2 fire extinguisher or water immersion. Different near Surface Mounted (NSM) including rope and strip were used to repair the damaged beams. A four-point flexural test specimen's response is recorded. The results demonstrated that, depending on the heat-shock treatment, both compressive and tensile strength decreased significantly (66-42% and 74-30%, respectively) of the control specimens. The flexural capacity of high-strength RC beams decreased to 88.2–95.1% of the control specimens after being subjected to different cooling regimes. However, when CFRP ropes and strips were used for repair, the flexural capacity of each specimen was restored to a minimum of 107% and a maximum of 177% of their original flexural capacity. Among the repair configurations, the side trapezoidal profile and bottom NSM were found to be the most effective. The failure modes shifted from flexural failure in the control specimens to shear or a combination of shear and CFRP rupture failure in specimens repaired using CFRP, except for those repaired with straight-line side NSM.