Abstract: The structure of low-pressure outer cylinder of the steam turbine is complex, and it is difficult to correct the deformation once the deformation occurs. In general, it needs to be returned to the factory for treatment. For the equipment located in the overseas, due to the multiple transport, collision, the cylinder deformation is serious. In the case of inconvenience to return factory for repair, according to the mechanism of heat expanding cold shrinking of metal materials, use simple instruments to straighten the deformation, and several corrective methods were compared. Select steam turbine steel plate location for heating, take the triangle shape for heating, so as to realize the deformation straightening of steam turbine. In a short time, the deformation problem was solved, and the follow-up construction period was guaranteed.