Abstract: For three unstable landslides of C area of Bayan Obo Iron Mine, with data of engineering geological exploration and rock mechanics test, the paper analyzed and calculated several measures for the secondary reinforcement including cutting slope, reinforcement by anchor cable and grouting by use of 5.5 edition of Lizheng soil analysis software and Canadian rock slope stability analysis software SLIDE5.0, and determined whether the secondary reinforcement measures are effective through the calculated safety factor. The analysis and calculation result showed that the secondary reinforcement measures can make safety factor of the most dangerous landslide to achieve 1.186, which meets requirement of designing safety factor of landslide's stability. At last, it proposed several notices about implementation of the secondary reinforcement measures.