Abstract: A new experiment of white light fringes has been developed. When Lloyd＇s mirror interference is combined with grating diffraction the fringes for different colors produced by white light source can be coincident, thus the white and black fringes will be observed. The theory, apparatus and method are introduced, and the key points of observation and measurement and data resuhs also are given.

Key words: Lloyd＇s mirror, grating diffraction, white light interference, white and black fringes