Abstract: Badly bleeding and oppression occurred to 4^# process oil tank at Xi Da tan pumping station in Gela oil pipeline resulting from valve leakage and out of order in dip hole seal, mechanical breather valve and hydraulic safety valve led to serious deformation of oil tank, with surrounding sticking up, the first ring steel plate of tank shell bursts to a rent 3 mm in width and 150 mm in length, which resulted in large amount of oil leakage. After a series measures were taken, drained oil gas, electric welding with reinforcement plate upon the rent in oil tank, positioning treatment to the deformed part, the oil tank is recovered to its original function. It is three years after the oil tank's rehabilitation, abnormal leakage event never occurred from the day when it put into operation, which states that the rehabilitation is ideal.