For all of the interferometers, alignment has played a key role in manufacturing them. Alignment goals are reproducible results across systems, easy to use and understand, altering overall mechanical design as little as possible, using the loosest tolerances required to achieve results. This paper describes four typical interferometers and their alignments. They are 1.06um interferometer, 24" large aperture phase shifting interferometer, Ritchey-Common testing and microscope interferometer as well.