Abstract: A method for repairing/strengthening and crack arrest of pipe, especially metal pipe, in which, first, to cover an insulated material on the position needing repairing/strengthening and crack arrest, then to lay a high strength fiber composite material. The modulus of elasticity of the material used in the invention is close to the metal pipe's, it can be integrated with the pipe and bear the internal pressure with the pipe, thus the final composite pipe reaches required bear capacity, such as, the original most operation pressure of pipe can be recovered; and it can take effect for crack arrest of pipes when pipes happen burst accident. Otherwise, because of the insulated material is used on the bottom layer, it prevent thoroughly from galvanic corrosion between pipe and strengthening material.