To explore the stress field characteristics of underground caverns under complex geological conditions, Yebatan hydropower station, located in Sichuan Province, is taken as the engineering background. A three-dimensional geological model of engineering region is established, which is based on the results of geological investigation. The regression analysis of ground stress characteristics is carried out in combination with the measured ground stress, and then, the evolution of the magnitude of ground stress in the whole engineering region is revealed. Finally, the stress orientation and magnitude characteristics of the stress field of the deep-buried underground caverns under complex geological conditions are studied, and the internal mechanism of stress field evolution is discussed.