Abstract: TWhen pressure of oil pipeline is increased instantaneously to exceed the safety limit preset of relief valve, the pressure will be released into the relief pipeline or storage tank through the relief valve to protect the oil pipeline. However, the function of relief valve is failed in a way due to frequent leakage. Observation to an unpacked relief valve revealed a phenomenon that the sealing face of it was damaged. The origin via analysis was discovered in 3 facets as follows: (1) the conehead of relief valve did not move to the reset position due to the low spring rate and blocking from solid particles (2) failed sealing parts were subjected to aging and erosion from solid particles and (3) the oil contained slight solid particles could not be filtered, which resulted in failed sealing to leak. In this paper, enough spare parts preparation, hydrostatic pressure test after an operation of relief valve and proper installation of filter were included as solutions.