Abstract: The distribution of geostress fields of deeply incised valleys in southwestern region of China is highly distinctive, exerting a significant control effect on engineering construction.The evolution of a valley and the valley morphology have a substantial influence on the distribution of stress fields in these deeply incised valleys.This study adopts an analysis method for the stress field in deeply incised valleys that incorporates the incisional effects of valley evolution, combined with typical engineering cases, to explore the influence of valley evolution on the development and distribution of the stress field in deeply incised valleys.A geological generalization model of a valley was established with slope height, valley bottom width, and slope gradient as variables to further analyze the influence of different valley slope morphologies on the development and distribution of stress fields in deeply incised valleys.The research findings indicate that the calculated results of the valley in-situ stress, which take into account the incisional effects of valley evolution, are more reasonable.The direction of the maximum principal stress deviates 5° to 20° towards the slope surface, with an overall decrease in the maximum principal stress.The magnitude of the maximum principal stress at the valley bottom can decrease by up to 30%, and the distribution range of stress concentration and high-stress zones are also reduced.As the slope height increases, the stress differentiation along the valley slope becomes more pronounced, and the maximum principal stress at the valley bottom increases.With widening of the valley bottom, the maximum principal stress of the rock mass in the middle of the valley bottom decreases, and the stress concentration zone shifts from the valley bottom towards the foot of the slope.As the slope angle increases, the maximum principal stress of the rock mass near the upper surficial part of the valley slope decreases, while that of the rock mass near the valley bottom increases.When the slope angle increases from 30° to 75°, the maximum principal stress at the valley bottom can increase by up to approximately 68%.The research outcomes can provide references for engineering construction and the stability analysis of rock and soil masses in the deeply incised valley regions of southwest China.