In the construction of roads in mountainous areas, the high-filled steep slope embankments are often encountered. The engineering treatment measures are generally taken to excavate the steps along the substrate. Although the effectiveness of this treatment has been proved by a large number of projects, its stability analysis model is not definite. Taking the high-filled steep slope embankment formed by a main trunk road in Chongqing as an example, the stability analysis method of high-filled steep slope embankment after the treatment of substrate excavation steps is discussed.