Abstract: With the background of an open-pit mine slope where two massive landslides happened, the open-pit mine slope was scanned with 3D laser scanner characterized by high mapping speed, high precision and large amount of data. The key areas were scanned especially where two landslides had happened. Based on the comprehensive improved ICP algorithm, the multi-station scanned cloud data were spliced to complete the 3d model reconstruction of the open-pit mine slope with the length of approximately 2 kilometers. The results of the study show that the 3D laser scanning result is consistent with the characteristics of actual engineering, is a fast and effective way of constructing digital model of open mine slope.