The invention provides a SLAM method applied to a multi-lens combination panoramic camera, which well realizes the automatic positioning and map construction functions of a vehicle-mounted multi-lenscombination panoramic camera, and achieves a high positioning accuracy of 0.1 m level without resorting to an expensive GPS/IMU integrated navigation system. The method firstly performs camera calibration on a multi-lens combination device, and then establishes a parallel three-thread, wherein the pose tracking thread mainly completes system initialization, feature extraction on a panoramic image,matching and projection, pose solution optimization and selection of key frames; The sparse map construction thread is mainly responsible for establishing sparse map points according to the initial posture and matching points, optimizing the camera posture and map points locally, and eliminating the wrong map points and redundant key frames. The closed-loop correction thread is mainly responsiblefor detecting whether the motion of the camera has returned to the previous position (i.e. Closed-loop), adding closed-loop constraints to correct the posture and global posture and map point optimization (i.e. Global beam adjustment).