Slope-cutting and load-reducing for mountain bodies of various lithologies is an important job in the mine geological environment control project. Taking a mine environmental control project in Jiangsu Province as an example, comparison and optimization is made of four methods: open rock blasting method, expanding agent crushing method, carbon dioxide fracturing method, and mechanical crushing method for cutting hard rock on high slopes. Based on the analysis of the key points and difficulties on the project, carbon dioxide cracking was selected. This paper introduces the construction technology and process of the project in detail, summarizes the relevant experience, and presents further thought on the carbon dioxide cracking method.