Abstract: In order to investigate the repair effect of carbon fiber reinforced epoxy resin composite on the ring-corroded N80Q steel pipe, the mechanical properties of the repaired steel were studied by numerical analysis and full-scale blasting test. The effects of axial length, depth and repair layer thickness on the repairing effect were analyzed. The results show that the carbon fiber/epoxy composite has a remarkable effect on repairing the N80Q steel pipe and the bursting pressure value of the 6 mm deep defect pipe is raised by 0.985 times after repaired by the carbon fiber/epoxy composite; the axial length of the defect has little effect on the strength of the N80Q steel pipe after repaired by the carbon fiber/epoxy, and as the axial length of the defect increases, the pipe burst pressure value only gets reduced by 3.5%; the depth of the defect has an obvious effect on the strength of the N80Q steel pipe after repair:Compared with the non-defective pipe, the burst pressure value of the 6 mm deep defect pipeline is reduced by 9.9%, and the burst pressure of the 7 mm deep defect pipe is reduced by 20.6%.