This paper made a tentative in-situ nondestructive study of components of single fluid inclusions from No.3 granitic pegmatite vein in Altay of Xinjiang by SRXRF. The authors improved micro-vidio lightning facility by which better, faster and more precise visual effects could be obtained, and the results are more reliable. Studies show that most fluid inclusions of No.3 granitic pegmatite vein have relatively high concentrations of Zn, Sn, As and REE which may be the characteristics of endogenous magmatism and crustal source.