Abstract: With the high and steep slope of Nanfen Open-pit Iron Mine as the support to make the theoretical research，and based on the understanding of the engineering geology，the deformation and failure of slope rock mass is studied deeply，and the statistical survey on its joints are made by the partition to determine the failure modes of the stope slope and analyze the stability status and the development trends. So，if the failure mode is confirmed distinctly，the landslide' sliding direction，size，shape and its mechanism will be all clear. And then the slope is reinforced，protected and monitored pertinently. It has important social and economic significance in ensuring the stability of high steep slope and keeping sustainable development of open pit mine.

Key words: Open iron ore, High and steep slope, Joint, Failure mode