A positioning method, a positioning device, a positioning system, a storage medium, and a construction method for an offline map database. The positioning method includes: obtaining a current image information, and extracting a visual feature in the current image information; matching the visual feature in the current image information with a key frame in an offline map database, and determining a candidate key frame similar to the visual feature in the current image information, wherein the offline map database is generated based on a global grid map and a visual map; and determining a pose corresponding to the candidate key frame, and converting the pose to coordinate values.