On the basis of distribution network operation efficiency evaluation model, big data mining analysis of distribution network operation efficiency is carried out by using the obtained file and operation data of millions of the distribution network main equipment in 2014. The equipment include high voltage transmission line, main transformer, medium voltage distribution line and distribution transformer. The mining process is divided into three stages: business understanding, data preparation and data mining. Firstly, in the stage of business understanding, the data mining goal is made, the data requirement is cleared and the business scenarios are designed. Secondly, in the stage of data preparation, the data collection, checking, repairing, cleaning and reconstruction are carried out. Then, in the stage of data mining, using the selected data mining analysis model, cluster analysis and association analysis is carried out, and the monitoring analysis is further made. Through in-depth excavation of the relevant influencing factors of operation efficiency, positioning the existing problems in order to make the development of distribution network more coordinated, and the operation more economical.