The ore-forming solution and the origin of silicon in Xiuyan nephrite were studied by means of H-, O-, Si-and S-isotope analyses. TheδD values of Xiuyan nephrite change narrowly from-70‰ to-76‰, while theδ18O values change from 8.1‰ to 13.3‰. The study shows that the compositions of hydrogen and oxygen isotopes in the ore-forming solution of Xiuyan nephrite lie in metamorphic water region, therefore Xiuyan nephrite was formed in metamorphic solution. The δ30Si values of Xiuyan nephrite range from-0.2‰ to 0.5‰, these values overlap those of the metamorphic rocks, and differ from marbles. So it can be concluded that most silicon atoms in Xiuyan nephrite came primarily from metamorphic water, and some of them were derived from the silicious band and flint concretion in marbles. Theδ34S values of pyrites and pyrrhotite which are paragenetic with Xiuyan nephrite change from 8.2‰ to 18.0‰, it suggests the sulphur in ore-forming solution was not derived from mantle, but from metamorphic water.