Accidents such as gas explosion and collapses often occur in coal mine production, in order to quickly determine the location of the injured and carry out rescue, the localization of a mobile robot was studied by using the open source monocular ORB-SLAM2 algorithm based on the existing mobile robot platform. The simulation experiments were carried out under the sufficient light sources condition and the dark condition with auxiliary light sources respectively, and the motion trajectory of the mobile robot was obtained, which provides the data foundation for the robot localization in the actual underground rescue process.