Abstract: Based on the characteristics of peak morphological parameters under different stages of karst development and the indicative effect of fractal characteristics of surface karst to the development of underground karst, this paper studies the morphology of ground karst in a karst tunnel area by using morphological parameter statistics and fractal theory, analyzes engineering geological conditions under different development stages and intensities of karst, and proposes relevant measures. Using the Baihushan tunnel in Yunnan as an example, the karst morphology of a tunnel area is determined from early to mature stages through peak morphological parameter statistics, a further analysis of the karst development degree of different strata is performed based on the fractal characteristics of the karst depression and contour line, the underground karst morphology is predicted and rational suggestions concerning tunnel construction are provided.