ABSTRACT: In this paper, a new loss allocation method is proposes, which is based on the complex power flow tracing. Firstly, constructed a new analytical model of transmission line, and the parameter analytical model is determined by the power flow; secondly, transmission line model can be more rational to solve active and reactive loss cross effect of active and inactive power flow; the method proposed in this paper can solve the problems of network loss allocation loop flow. The theoretical analysis and the simulation results verify the correctness and effectiveness of the proposed method.