Abstract: A multi-sensor fusion SLAM system and a robot. The system operates on a mobile robot and comprises: a visual inertia module, a laser scanning matching module, a loop closure detection module, and a visual laser image optimization module. According to the multi-sensor fusion SLAM system and the robot, the calculation amount of laser matching constraint optimization can be reduced by using a voxel subgraph so that the pose calculation is more accurate, accumulated errors of long-time operation of the system can be corrected in time by means of sufficient fusion of modules, and the robustness of the system and the accuracy of positioning and mapping are integrally improved.