The utility model provides an auxiliary device is laid to pipe circular seam welding after heat treatment heat preservation cotton, movable frame body establish roller group and last listrium, going up the listrium and establishing the lift integrated configuration, the lift integrated configuration includes worm, worm wheel and motor, and the worm is connected with lift platform and worm wheel, motor dress worm wheel, go up the listrium and establish round hole and the up -and -down motion that lifting guide post passed lift platform, lift platform establishes bed hedgehopping support body, spring board and radian regulation structure, the cotton that keeps warm is established to spring steel sheet upper surface, its structural design is reasonable, can reduce the construction degree of difficulty and workman intensity of labour effectively, improves the construction security and lays the reuse rate of frock, improves working environment, practices thrift the cost.