A method for amending layout patterns is disclosed. First, a layout pattern after an optical proximity correction is provided, which is called an amended pattern. Later, a positive sizing procedure and a negative sizing procedure are respectively performed on the amended pattern to respectively obtain a positive sizing pattern and a negative sizing pattern. Then, the positive sizing pattern and the negative sizing pattern are respectively verified to know whether they are useable. Afterwards, the useable positive sizing pattern and the negative sizing pattern are output for the manufacture of a reticle when they are verified to be useable.