Reliability tracking is a major method to identify weaknesses links (inappropriate installed transformers, lines and etc.) in power system, the contribution rate of each component on system reliability index is obtained by tracking analysis, then, the weakness links in power system can be found. Double-sharing model of distribution network element reliability is proposed based on distribution network Section algorithm and reliability tracking criteria in this paper, and reliability tracking indicators is analyzed deeply, and the weaknesses links in power system is identified based on tracking results, then putting forward reliability improvement measures. Application of the principles of reliability track and double-sharing model, IEEE RBTS BUS6 system and a given actual distribution system as examples, identify the weaknesses of these two systems, and puts forward the reliability improvement measures.