The transmission lines fault location system consists of fault location device and master station， the difference between the fault location system applied to smart grid and that of traditional system is presented. In comparing with existing system， in fault location device for smart station distributed sampling is adopted and access to electronic transformer is provided. In addition， device communication based on IEC 61850 standard in substation is also solved. In the meantime， the method to promote fault location system reliability with regional grid information in master station is also studied， and a failure analysis system is developed using transient quantity information， which results in ability for initial diagnosis ability of power grid fault.