Abstract: The monitoring results of the forces applied on a soil-nailing support structure in a high slope project with weak rock and relative displacements are presented in this paper. The analysis of the monitoring data reveals that the working principle of soil-nailing support is different from not only an anchor structure, but also a soil-nailing wall. According to the monitoring results of the horizontal displacement in the slope during the project construction, the supporting parameters, cutting depth and supporting time for the slope were adjusted so that the high slope was kept stable on the whole.