Aimed to tackle the problem in fault diagnosis of sucker rod pumping system, based on the analysis of kinetic behavior in sucker rod pumping system, the models for vibration mechanics and fault diagnosis of sucker rod pumping system in directional well in consideration of flexibility of hanging system are established. A method to diagnose the fault of sucker rod pumping system based on B/S Mode is studied. On this basis, fault diagnosis system of sucker rod pumps which is based on B/S mode software by using Internet and Web technology is developed. An example of calculating is presented, whose correct result justifies the validity of this system. The fault diagnosis based on B/S mode has great significance for preventing blindness of downhole work, improving the system efficiency, reducing the oil extraction cost and raising scientific management level of oil veil. Meanwhile, it improves enterprises information-based degree of oil field, lays the foundations of realizing "Digital Oil Field".