Abstract: The impact reshaping is a technology in commonuse for repairing damaged casing. The mechanical model of cement loop is built basedon the impact reshaping technology and wave technology. The balancedsite-shape of the drill pipe and the impacting force caused by the drillpipe are obtained by subsections based on the mechanical model of a cantileverbeam. According to the stress state and Mazars damage mechanical modelof brittleness materials, a damage mechanical model of cement loop is built andthe damage state is calculated. The calculated results are compared againsttesting results and the error is around 2.7%.