Abstract: To investigate the primary and secondary relationships as well as differences in sensitivity factors under two common failure modes of embankment soil slopes: deep-seated overall circular sliding and shallow slope-parallel surface sliding. Based on the measured shear strength parameters of red bed mudstone embankment fill in the southwestern region, employing an orthogonal experimental design for multi-factor sensitivity analysis and utilizing the Geo-slope slope stability analysis software, this study separately analyzed the influence of individual strength parameter variations on the safety factors for deep and shallow stability of an embankment slope. It investigated the sensitivity and hierarchy of four factors-slope height, slope ratio, cohesion, and internal friction angle-under these two failure modes, and compared their differences, and discussed the implications for practical embankment engineering.The results indicate that: Under normal conditions, the safety factors for both deep-seated and shallow stability of an embankment slope exhibit a linearly increasing trend with the enhancement of soil strength parameters. The primary and secondary relationships of factor sensitivity for deep-seated stability versus shallow stability in a homogeneous slope are distinctly different. For the former (deep-seated stability), the order of factor sensitivity from primary to secondary is as follows: slope height, slope ratio, internal friction angle, and cohesion. For the latter (shallow stability), cohesion is the most sensitive factor, followed by slope ratio, internal friction angle, and slope height. Moreover, the ratio of the safety factor range for cohesion to that for slope height reaches 6.3. This demonstrates that for the deep-seated stability of embankment soil slopes, geometric parameters are more influential than mechanical parameters. Consequently, greater emphasis should be placed on the construction height and slope ratio during design. For shallow slope stability design, increasing attention must be paid to the loss of soil cohesion after water immersion to prevent shallow instability failures.