Abstract: A failure diagnosis system of pump unit is developed by Weifang Oil Transportation Administration of Sinopec and University of Petroleum (Beijing). This system, characterized by simple operation, flexible in use and high accuracy in failure diagnosis, can be used to monitor the operating state and failure diagnosis of pump unit to prevent the electric motor and pump shaft from damaging, bearing from burning out and pump body from vibration. With this system, the operating of pump unit can be kept under a safe state.