The principle of lining repair is to have a new pipe lining the lining of the original pipe, which has a smaller diameter than the original pipe. However, due to pipe and other reasons may be the new pipe's overwater capacity compared with the original is not much different, the advantage of this method is that the construction of road traffic and other underground impact is very small. However, the disadvantage is that the pipeline appears large dislocation, deformation can not achieve the desired effect. The pipe diameter, slope, etc. of the new pipe depend entirely on the relevant characteristics of the old pipe.