Abstract: In our country, governance after mining is the passive mode for open-pit coal mines, a new theory of green mining is proposed based on the principle of sustainable development, its goal is to achieve efficient exploitation of resources and minimal environmental impact. The concept of green index is introduced, which is used as the objective function to evaluate each process step during the design or construction stage of open-pit coal mine, and also, the green index evaluation system diagram and modeling method is proposed. Through the green index evaluation system, the weak link of open-pit coal mine is found to realize the coordinated development of open pit mining and environmental protection after optimization and improvement.