Abstract: Oil pumps are frequently shut down due to overtemperature of bearings at non-driving end. The failure is reflected by rising temperature of such bearings out of limit. In essence, axial force becomes gradually out of balance because shot blasting and erosion are frequently generated at interstage labyrinth balance set of primary pump by high-pressure oil flow with impurities that runs through balance holes, and consequently excess axial force can not be balanced out by thrust bearing. It is shown by further analysis that pump failure rate (3^# > 2^# > 1^#) is dominated by process piping arrangement. Accordingly, it is concluded that the following measures shall be applied to operation management, such as adjusting screen mesh of incoming filters, shortening filter cleaning cycle and strengthening pigging of major pipe sections. Additionally, it is necessary to adopt novel high-efficiency strong magnetic cleaning devices in station process. In practical operation, the amounts of impurity that move into primary oil transfer pump is effectively controlled in a certain range due to the application of above mentioned measures, so the component parts inside the primary pump (especially interstage labyrinth balance set) are protected well. In this way, long-period operation can be guaranteed for primary pumps.