Abstract: TCA series of automatic total station was used to monitor the deformation of Nanfen Open Pit Iron Mine which has already formed a 492 m high-steep slope at stope footwall.After 3 years of continuous monitoring，a large number of precious data have been achieved.Through the processing and analysis of the data，the earth's surface will produce significant deformation and accumulated deformation will exceed 200 mm，and the peak deformation reaches 650 mm when the earth's surface displacement monitoring curve enters into “the accelerated mutation stage”.Monitoring practice shows that the monitoring technology has features of high reliability，high precision and simple operation，so it is worth promoting in the field of high-steep slope deformation monitoring.

Key words: High-steep slope of open pit mine, Deformation monitoring, Mining, Fracture characteristics