Abstract: In view of the current situation that a large number of 10⁵ m³ crude oil storage tanks reached the repair cycle, based on safety assessment, this paper presents a set of delayed maintenance technology for storage tanks, involving expert system, on-line inspection, risk based inspection and so on. This paper will focus on solving the technical problems,such as how to extend the repair cycles, and how to build a safe environment. It is expected that the operation efficiency of the storage tank will be improved and the production cost will be greatly saved.