In view of the current situation that the existing line loss allocation methods do not reasonably consider the actual impact of distributed generator (DG) grid connection on the line loss of distribution network, this paper proposes a line loss allocation method which takes into account DG impact levels and weight characteristics. Firstly, a set of impact index system is designed in terms of the planning, operation and management of distribution network so as to comprehensively characterize the impact of DG grid connection on distribution network. On this basis, the line loss allocation strategy is developed to deduce the economic cost of distribution network. Secondly, the value of index weight is given by the order relationship analysis method (critical-g1) which is combined with the critical method. The index weight characteristics is comprehensively analyzed from the subjective and objective perspectives, thereby, the degree of influence of different indicators on line loss is emphasised. In addition, the relation relationship between each index and line loss is not definitely linear. Thus, the impact levels are classified and the value of impact factor is set. Afterwards, the index weight and influence factor scores are employed to calculate the coefficient of line loss allocation correction, and the DG allocation power is modified on the basis of power flow tracing method. Finally, a typical day of a distribution network with DG is included as an example to verify the effectiveness of the proposed method.