Based on the in-depth geotechnical trench excavation tests on the full slope scale of typical dolostones, the spatial coupling development characteristics between the soil and upper epikarst zone on dolostone slopes have been preliminarily clarified combined with the field measured data,. The results indicate that: 1) The thickness of soil and upper epikarst zone on dolomite slopes gradually increases down the slope. The average thickness of the upper epikarst zone on a slope scale is 50 cm, with an average volume of 0.47 m3/m2, accounting for 43.9% of the total volume of the soil profile, indicating that the ecological function of epikarst in karst regions is extremely important; (2) The geotechnical structure of the dolomite slope exhibits strong spatial heterogeneity. The spatial heterogeneity of the underlying upper epikarst zone (C+C0 is 18.88) is significantly higher than that of the overlying soil layer (C+C0 is 15.84) ; (3) The overall soil thickness,,especially the thickness of soil layer B, is significantly positively correlated with the degree of weathering in the epikarst, indicating that the increase in soil thickness promotes the weathering of the underlying epikarst, and there is a clear coupling and collaborative development relationship between soil and upper epikarst zone The soil and upper epikarst zone in karst regions have evolved in a mutually reinforcing manner, with the epikarst below the soil layer potentially acting as an essential substrate for the karst ecosystem. The soil thickness and the depth of its B horizon exhibit a significant positive correlation with the thickness of the epikarst, which may be critical parameters for predicting epikarst depth on karst slopes. The evaluation of karst water and soil resources demands a holistic approach that encompasses both soil and the underlying bedrock weathering layer.