Strengthening and repairing of structures is an inseparable part of building which has been considerate from old. In recent years, using of FRP composite laminates in strengthening reinforced concrete structures and even steel structures is very considerate. One of the most important FRP applications is bending strengthening reinforced concrete beams with bonding FRP on the tension face of beam. Basic problem in strengthened concrete beams with FRP laminates is premature debonding of sheet from concrete surface which induced precocious failure structural member. Of most important reasons of debonding is unpreparedness of concrete surface in order to good bonding to composite sheet. Surface preparation of concrete is typically associated with such constraints as expense of operation, inaccessibility easy to the member, creation of dust and pollution of environment and thereupon impossibility of servicing of structure in during strengthening operation. Thus in this study, possibility substituting holing new method to surface preparation in bending strengthening concrete beams with FRP sheets investigated. Also attempted which deferent parameters of this method investigate. The experimental specimens used in this study included 120 prism specimens of dimensions 100×100×500 mm which subjected to 4-point flexural loading. The specimens were divided into deferent groups and strengthened with FRP composites to deferent methods. Also several specimens tested in state without strengthened. Used methods for strengthened specimens are included without surface preparation, with surface preparation, holing, holing with nailing and holing with anchoring sheet in end holes. The results indicated that surface preparation of concrete can increase ultimate failure load. Using of holing lieu surface preparation cause increasing ultimate failure load. Also with using supplementary methods nailing and anchoring strengthening sheet in end holes, in addition to increasing ultimate failure load, failure mode change from debonding to rupture of sheet too. Key Words: Bending Strengthening, Debonding, FRP Composite laminates, Surface preparation, Holing.