The bond strength between fiber rein forced plastic /polymer composites(FRP)sheet and concrete was studied by experiment on a simple shear test s et-up with emphasis on the effects of the bond length,support height,loading offset and FRP-to-concrete width ra tio.The test results were compared w ith those obtained from the Chen and T eng's bond strength formulas.Following c onclusions are drawn from this study:(1)there are two kinds of failure modes,namely FRP debonding failure and con crete tension-shear failure;(2)the bond length,loading offset and FRP-to-concrete width ratio have significant effects on bond strength while the support height also has certain effect;(3)the results obtaind from Chen-Teng' s bond strength formula agree well wi th the test results,provided the total bond length is no less than the effective bond len gth.