Long-term changes in power grid operating status are tracked, making use of production and dispatching information, and computer, network and power system analysis technology. Factors that affect power grid operating characteristics are sorted out. The longitudinal analysis of the grid state is realized by classification and identification of power grid weak links. The key weaknesses are guaranteed to be resolved as soon as possible. Power grid security, stability, reliability, economic operation is also guaranteed. The frame design of the weak link tracking and analysis system is proposed. The practical case demonstrates the feasibility and effect of the power grid classification method, and the application prospect of the technology is also prospected. The objective of the technology is to achieve safe operation margin, pre-existing countermeasures, decision-making basis.