The invention provides a multi-focal-length stereoscopic vision simultaneous positioning and mapping implementation method and system, and belongs to the technical field of automatic driving, automobile environment perception and intelligent cabins. The method comprises the following steps: 1, installing a multi-focal-length stereo camera, and calibrating a projection matrix Pl of the multi-focal-length stereo camera and a projection matrix Pr of a right camera by using an improved multi-focal-length camera calibration method; 2, extracting the ORB feature points of the image based on the image pyramid, and increasing the number of extracted ORB feature points for the part, with the same view as the long-focus camera image, in the short-focus camera image; and 3, stereoscopically correcting the ORB feature points by using the multi-focal-length calibration parameters, stereoscopically matching the ORB feature points to obtain the three-dimensional positions of the ORB feature points, and finally solving the pose of the ORB feature points. According to the invention, the positioning precision same as that of a short-focus standard three-dimensional SLAM can be realized, and long-distance scene mapping can be realized.