In order to discuss the best performance price ratio of fiber reforcement plastic（FRP） concrete with cracked concrete structure, the effect of FRP bonding length on the fracture parameters of three point bending beam of concrete was studied through the damage and fracture test of different length fiber cloth adhered to the three point bending beam of concrete. The crack initiation load of FRP reinforced concrete cracking test was tested by placing a strain gauge on the surface of a three point bending concrete specimen with cracks and the displacement curve of the load crack opening was measured by a clamp extensometer. According to the improved calculation formula of fracture toughness, the effective crack length ac, instability toughness Kun′IC and crack toughness Kini′IC of three point bending beam specimens with different FRP adhered length were calculated. The test results show that the peak load of FRP reinforced concrete increases with the increase of FRP adhered length for the concrete three point bending beam with the same initial crack depth, the instability toughness and the crack toughness of the concrete increase first and then decrease with the increase of the bonding length of the FRP. When the length of the FRP adhesion is 25mm, the average value of FRP instability fracture toughness and initiation fracture toughness reach the maximum, crack resistance effect is the best. Based on acoustic emission(AE) non destructive testing technology, the acoustic emission parameters of the above mentioned concrete during fracture process are identified and collected.The optimum bonding length of FRP for concrete three point bending beams strengthened with 04 initial crack depth ratio is 25mm.