On-line testing is currently a commonly used testing method for pressure equipment in complete petrochemical plants,which can improve the long-term safe operation of production equipment in petrochemical enterprises,reduce production costs and maintenance costs,and enhance the competitiveness of enterprises.Through the analysis of the application characteristics of seven common on-line testing technologies:acoustic emission testing,electromagnetic ultrasonic testing,pulse eddy current testing,balanced field eddy current testing,array eddy current testing,ultrasonic guided wave testing and digital flat panel imaging,combined with the two damage categories of corrosion thinning and environmental cracking,the selection suggestions of on-line detection technology of pressure vessels and industrial pipelines were given.