A localization and mapping method is for localizing and mapping of a moving apparatus in a moving process. The localization and mapping includes an image capturing step, a feature point extracting step, a flag object identifying step and a localization and mapping step. The image capturing step includes capturing an image frame at a time point among a plurality of time points in the moving process by a camera unit. The feature point extracting step includes extracting a plurality of feature points from the image frame. The flag object identifying step includes identifying whether the image frame includes a flag object from the feature points in accordance with a flag database. The flag database includes a plurality of dynamic objects. The flag object is corresponding to one of the dynamic objects. The localization and mapping step includes performing localization and mapping in accordance with the image frames captured and the flag object thereof in the moving process. Therefore, it is beneficial to effectively reduce localization errors and mapping misjudgments.