Abstract: When producing the large-sized heavy-wall pipe especially the P91 or P92 high-pressure boiler pipe, the drive torque forcing on the roll by the main drive system of the Φ460 mm cone type piercer is insufficient.So while keeping the original main motors and electric drive devices, the main drive system of the piercer is revamped by appropriately increasing the reduction ratio of the main reducer and changing the universal shaft.Relevant actual operation practice shows that the revamped main drive system of the piercer has increased the drive torque of the roll and can meet the requirements of batch production of large-sized high-grade steel pipes.