Abstract: Granite and its soil are widely dispersed over the southern part of China. There have been more and more granite soil high slopes along with the development of highways. Engineering geological properties of soil slope are different from the general soil slope for it's special formation process. There are important theoretical and practical significance to research such slopes. Monitoring is an effective method to research slope. It can identify the main controlling factors of slope deformation and failure and predict the long-term stability of the slope. The paper takes the example of a highway granite soil high slopes. The sliding zone is inferred here by the comprehensive analysis of appearance deformation monitoring data, inclinometer monitoring data and geological observation data. Then the slope deformation and failure characteristics are analyzed in details. The study shows that the optimal design and informational construction of high slopes can be achieved. It is also shown from the result that the hidden structural face in slope has very strong control effect on on slope stability.