Restructuring of Electricity supply industry introduced many issues such as transmission pricing, transmission loss allocation and congestion management. Many methodologies and algorithms were proposed for addressing these issues. In this paper a graph theory based method is proposed which involves Matrices methodology for the transmission usage, loss and transmission reliability margin (TRM) allocation for generators and demands. This method provides loss and TRM allocation in a direct way because all the computation is previously done for usage allocation. The proposed method is simple and easy to implement in a large power system. Further it is less computational because it requires matrix inversion only a single time. A comparison between proposed method and already exiting methods also presents. Results are shown for the sample 6 bus system and IEEE 14 bus system.