This paper deeply analyzes the formation mechanism and prevention measures of the south slope landslide in No.1 open-pit mine of Shengli Coalfield and reveals the key role of the weak layer in the slope stability. The complex engineering geological and hydrogeological conditions in the mining area, such as the uneven distribution of Quaternary strata, the monoclinal structure of coal-bearing strata, and the control of basin-edge faults, increase the risk of slope instability. In particular, the existence of weak mudstone layers and the softening of mudstone under the action of rainstorms have become the main risks of landslides. In view of these risks, this paper puts forward targeted prevention and control measures. Real-time remote sensing monitoring, like using high-resolution satellite imagery and InSAR technology, can detect subtle slope surface changes and measure displacements accurately to identify potential landslide risks in time, preventing disasters. Additionally, remote sensing integrated into drainage measures can detect water-related issues, optimize drainage system design, and monitor its operation, thus reducing the risk of landslides caused by water. These measures not only help to improve the safety production level of open-pit mines, but also provide an important basis for the prevention and control of similar mine landslides.