To solve problems of sampling, transport, storage and management of actual core, the technique of electronic core, which is used to replace actual core, is presented, and the establishment of electronic core database is put forward. Based on high-quality images  provided by high-definition borehole-TV, an electronic core model was established, and the database system of electronic core was formed in accordance with the principle of coupling between the image of  hole wall and the actual core. The system has functions of pre-processing, storing, searching, analyzing and plotting, as well as maintaining and managing of the electronic core. By using this technique, problems of the actual core can be effectively solved in project, and the efficiency of bore drilling exploration can be improved. At present, this technique has been applied to Wudongde hydropower station very well.  