Abstract: In view of the abrasion, scratches, pits and other defects on the surface of the roller ring caused by the steam pipe rotary drying operation for a long time in PTA unit. By using the method of "online turning of roller rings" to repair the surface of dryer roller rings, the practical application has proved that this method can facilitate the staff to carry out online detection, turning and grinding of the surface of roller rings on site without removing the roller rings, and control the surface roughness size, so as to control the maintenance quality, save time and labor, and greatly save the time of resuming work and production. So as to ensure the whole set of production equipment long cycle normal operation.