Construction of the low-carbon power grid plays an important role in promoting the low-carbon economic development of the entire society.The importance of establishment of the low-carbon power grid index system and its comprehensive evaluation model for the development of the low-carbon power grid is firstly discussed.Based on the concept of life cycle analysis，a comprehensive low-carbon power grid index system and a more refined central index system are designed in consideration of different aspects of coverage，and the meaning of each index explicated in detail.Furthermore，a comprehensive evaluation method is designed for the quantization of the low-carbon developing condition of different power grids.Finally，an example analysis is conducted based on the statistical data of some domestic power grids to demonstrate the actual application of the evaluation model.