China Telecom’s fifth-generation core (5GC) network is complicated owing to own characterizations of service based architecture and network functions vir-tualization, and thus is vulnerable of network failures. When a failure occurs, operations and maintenance (O&M) experts need to firstly analyze its root cause based on their professional experience; then recommending an available solution for the failure. However, 5GC network failures occur frequently, and most of them are similar; thus, inviting O&M experts to the 5GC network scene costs a super-long of time (hourly level) and wastes too much money. In this paper, we propose a knowledge&data-driven 5GC network Failure Location and Automated Mitigation (FLAM) mechanism. Particularly, FLAM illustrates the experts experience of different network failures using knowledge graphs. Four state-of-the-art machine learning algorithms are applied in FLAM to compare which one can better locate the root cause of network failures. Besides, a real-time checking module is designed to automatically diagnose the related network functions for network failures. Based on China Telecom’s real-wild data of network failures, the proposed mechanism is evaluated in the metrics of algorithm complexity and location accuracy. Experimental results show that the decision tree model has an accuracy of 99% for locating the root cause of network failures, which owns the best performance compared to the random forest, support vector machine, and k-nearest neighbor algorithms.