Disclosed are a fused ring pyrimidine compound, and an intermediate, a preparation method, a composition and a use thereof. The fused ring pyrimidine compound is a compound as shown in formula I, a tautomer, an enantiomer, a diastereoisomer, a pharmaceutically acceptable salt, a metabolite, a metabolic precursor or a prodrug thereof, wherein the above-mentioned compound is used for the preparation of a medicine for preventing, remitting or treating one or more of immune system diseases, autoimmune diseases, cell proliferative diseases, allergic disorders and cardiovascular diseases, and the compound has a strong inhibitory effect on the Janus kinase, FGFR kinase, FLT3 kinase and Src family kinase.
