Abstract: In order to meet the urgent need for quality monitoring and classification evaluation of recycled drill pipes,an automatic detection and classification operation line is developed to replace the currently-adopted manual operation.Composed of the MFL/UT combined NDT system as working with the drill pipe rotating,the automatic geometrical dimension laser measurement system and the automatic classification equipment,a net-worked control system is designed based on Local Area Network,Ethernet,MPI and PROFIBUS-DP,which is capable of integrating inspection data and classification information so as to realize the automatic collection/dis-tribution control of the production line.The actual site application result proves that the newly-developed control system that features reliable and consistant running has significantly improved production efficiency and product quality as well.