The invention relates to a line loss level evaluation method based on power grid characteristic difference. According to the method, line loss influence integrated factors such as the natural condition, the network structure, the power utilization structure and the power grid operating characteristics of each province or city or county are led in, an original single index only with the line loss rate numerical value size taken into account is changed into an index system which is composed of various indexes affecting line loss, considering the impact of all the indexes on the line loss rate, different weights are set, comprehensive calculation, analysis and evaluation are conducted, so that a scientific index system and evaluation criterion is established, and thus the advancement of the power grid line loss level evaluation method can be guaranteed. According to the line loss level evaluation method based on power grid characteristic difference, the traditional method that the line loss rate size is purely used for evaluating the line loss level before can be broken through, the quantitative evaluation method of the line loss level of a power grid at the same level is provided, the loss reduction potentiality of the power grid is exploited to the maximum degree, and thus the line loss management level of the power grid is improved.