Abstract: The ends of expandable profile liners are characterized by significant differences in configurations.Unaligned butts during welding results in seam low strength.In order to improve the alignment of the ends and the stability of the weld seam,a restoration device for the expandable profile liner(EPL) has been developed.By optimizing the shaping temperature and reducing restoration force,the toughness of the EPL can be improved effectively.Through optimization of the length of the restoration section,it is possible to reduce the risk of getting stuck.An inner mold with three valves reduced the possibility of stuck risks by allocating stress.The geometric configuration of the inner mold was optimized through a stress distribution analysis.Experimental results and field application results showed that the device has the advantages of high restoration precision,reduced restoration force,reduced friction and better anti-sticking.From the initial design,the alignment of butt weld can be reduced to less than 1 mm after the restoration from 4-5 mm before the restoration resulting in a greatly improved weld stability for the end restoration.The restoration device can improve the abilityand reliability of the EPL to pack complex formations.