The debates of light and being are important problem of Illumination and Peripatetic philosophy as the base of these philosophies. The light has very attributes same as realization, emersion, gradation (tashkik), needless, that specific to it non-light haven’t these attributes. One the other hand peripatetic philosophers study about being and knows it to the subject of metaphysic (mawjud be ma howa mawjud). The being has some quality as evident, generality, etc. that can be compare it by light and this article we trying to do it. Finally the role of light is not look the role of being like and being never is alike to light and have different quality of it.