Abstract: Basic principle.technical characteristics and research actualities about vertical storage tank on-line inspection technology in acoustic emission technique, ultrasonic inspection technique, robot technique and planar guided wave at home and abroad are introduced, and the latest progress in the research of planar guided wave for on-line inspection technology of vertical storage tank made by PetroChina Pipeline R & D Center is especially introduced.Teehnical issues existed in acoustic emission technique and planar guided wave technique for on-line inspection of vertical storage tanks are analyzed, and study and development of the on-line inspection technology for vertical storage tanks are put forward.