The present application discloses a method and apparatus for updating a map. An implementation of the method comprises: acquiring a laser point clouds obtained by scanning a surrounding environment and acquiring a periodic pose change of a vehicle in a scanning period; determining an a priori pose of the laser radar at a reference time in the current scanning period based on a known pose of the laser radar in a previous scanning period and the periodic pose change; performing motion compensation on the scanned laser point clouds to form a compensated point cloud frame; generating a partial point cloud characteristic map; matching the partial point cloud characteristic map with a map area obtained in a reference point cloud map, and correcting the a priori pose to obtain an a posteriori pose; and updating a three-dimensional point cloud map of a to-be-constructed area using the compensated point cloud frame.