The line loss of distribution network is an important assessment evaluation index of electric power company. For complicated circuits and many branches of distribution network, it is difficult to calculate the cost and benefit brought by refining line losses. Under this background, aiming for the comprehensive energy conservation and loss reduction of distribution network, the life cycle cost and energy conservation and loss reduction benefit indexes are put forward from the aspects of time dimension, component dimension and expense dimension on the basis of the spatial-temporal elements of energy-saving features. The comprehensive energy conservation and loss reduction results are evaluated to derive the optimal design scheme of distribution network comprehensive energy conservation and loss reduction by the improved VIKOR method based on AHP and CEDEA analysis. Then the feasibility and validity of the proposed evaluation method are verified and validated by the actual distribution network in China.