The expansion of general aviation airport construction will be an inevitable trend in the coming years, and the selection of the airport's site directly influences its safe and efficient operation. In the planning and construction process of general aviation airports, the selection of sites in mountainous and hilly areas poses greater challenges and limitations compared to flat terrain. A site selection index system for general aviation airports in mountainous and hilly areas is constructed based on three aspects: transportation conditions, construction conditions, and operational conditions. The fuzzy analytic hierarchy process is utilized to quantitatively evaluate site selection criteria. Building upon this, a decision model for general aviation airport site selection in mountainous and hilly areas is established using GIS（geographic information system）to obtain visualized results of the evaluation of airport site selection factors. It reveals the suitability of spatial distribution for general aviation airport site selection, providing a reliable quantitative basis for relevant decision-making. The model and methodology's usability is validated using the example of site selection for a general aviation airport in the east China region.