Abstract: Rock slope stability is one of the most critical issues for the safety production of an open-pit mine. Providing early warning signals and issuing accurate evacuation orders for rock landslides hold practical engineering significance. By collecting and analysing 32 rock landslide cases in the open-pit mine, it has been proposed that rockfall or slope movement acts as a precursor early warning sign of rock landslides. Following the safety monitoring standards for open-pit mines, the abundance of monitoring videos can provide valuable data for early warning of rock landslides. In this paper, the motion target tracking algorithm is utilized to identify rockfalls or slope movement areas from the monitoring videos. By setting appropriate thresholds, early warnings with leading time ranging from tens of seconds to hours can be provided for areas where landslides have initiated but not yet spread. An undisclosed open-pit quarry and the Yanshan open-pit mine are employed to demonstrate the proposed method. The results indicate that the rock landslides progress through four phases including occasional rockfall, small-scale rockfall, continuous rockfall, and overall landslide. For rock landslides with heights of 6 m and 30 m, the early warning leading time is 35 s and 113 s, respectively. The proposed rock landslide early warning method based on rockfall video monitoring holds extensive application prospects in open-pit mines. However, extensive field validation and further research are required.