Abstract: The time between overhauls (TBO)of refinery is a very important cycle in safety and management for the oil product storage and transportation system(PST system).The six measures must be taken for maintenaning the PST system : ① working out a safety plan, ② knowing well the detail information of the pre-maintenance equipments, especially the equipments modified reversly, ③ improving the preparation of construction, forbiding unqualified persons to work, ④ planing a reasonable construction progress, and coordinating in integrity, ⑤ paying more attention to the important role of blind plate in dangerous work, ⑥ laying stress on the acceptance check so as to control the quality of construction.The cases of pipeline leak and explosion caused by neglecting the six measures above are introduced in the paper.