Eco-geology is a science that studies the interaction between ecology and geological environment and its mechanism. The technical frameworks for eco-geological surveys based on geological formation for mountainous areas are summarized, through the project of "Comprehensive Geological Survey of National Ecological Civilization Demonstration Area in Chengde City". According to the three levels of survey, i.e., background (baseline) survey-small watershed survey -research on ecological critical zone, the eco-geological characteristics and function rules of Chengde City are gradually deepened. The survey at the 1:250000 scale can quickly identify the eco-geological background (baseline) of the whole area, recognize the eco-geological units, and quickly screen the eco-geological targets (dominant ecological resource areas and ecological environment risk areas) through the geological formation analysis and mapping; the survey with a key small watershed unit (at the scale of 1:50,000) is carried out for the selected target areas so as to identify the characteristics of dominant resources and evaluate the risks of ecological environment; surveys and researches on ecological critical zones of typical geological formation (at the scale of 1:10000) are carried out to reveal the three-dimensional characteristics and interaction mechanism of the eco-geological system and provide a basis for comprehensive monitoring and prediction of the evolution trend. The framework of "Demand-Survey-Application" is demonstrated based on the survey results, and corresponding suggestions are proposed for the land spatial planning, ecological industry development and ecological protection and restoration for Chengde City.