Since unpredictable faults may be encountered, the first overhaul is especially important for newly installed plants, as compared with the plants in service. Through analyzing the large temperature difference between the internal and outer surface of the high and medium pressure cylinder, it was inferred before performing overhaul that the cylinder stator may deform seriously. Thus, preparation had already been made for returning the turbine components to the manufacturer. Besides, measures including optimizing the sealing, reducing steam leakage and strengthening the dummy plate within medium pressure cylinder were also implemented, and higher economy and reliability were achieved.