The invention provides a method and a system for constructing a distribution network operation efficiency evaluation model. The method comprises obtaining operation mode of a power distribution system, pressure level and power distribution system type information; according to the operation mode of distribution network and the type of distribution equipment, combining the multiple pieces of distribution equipment, and the key parameters of the combination of the distribution equipment are calculated; according to the key parameters of distribution equipment combination, the evaluation model ofdistribution equipment combination operation efficiency is established; according to the evaluation model of distribution equipment combination operation efficiency, the evaluation model of distribution system operation efficiency is established. The construction method and the system of the distribution network operation efficiency evaluation model proposed by the invention can comprehensively consider the operation mode of the power network, and more accurately reflect the real situation of the distribution system operation efficiency, thereby providing effective guidance for the planning and construction of the distribution system and the optimization of the operation mode.