The safe operation of the transmission line is the foundation of building a strong and smart grid. Accurate comprehensive quantitative assessment of line state is the key to ensure safe and reliable operation. How to transform scattered, massive, multi-state status information into knowledge and determine the health status of the device is very important. Based on comprehensive investigation and analysis and combined with the actual of repair work in Shanxi transmission line state, effectiveness and practicality of the model is verified by case analysis. The work is proposed to lay a solid foundation for the building of strong and smart grid.