In order to capture the descent stage of the δ τ relationship of FRP to concrete interface, an early designed “double pull” specimen was modified. A horizontal loading scheme by using a MTS electro hydraulic servo system was designed. Nine modified specimens were prepared, and eighteen whole measured δ τ curves with the descent stage and ultimate slip were obtained. A δ τ regression equation was provided based on the tested data. The tested 3 key parameters (the maximum bond stresss τf, the corresponding slip δf, and the ultimate slip δu) of the bond slip relationship of CFRP to concrete interface were ranged within 227519MPa, 00310077mm，and 00870223mm under the given experimental conditions.