The present invention relates to a pyrrolopyrimidine five-membered azacyclic derivative as a novel JAK kinase inhibitor, and use thereof in a preparation of a pharmaceutical product for preventing and/or treating an indication related to a JAK kinase function. The pyrrolopyrimidine five-membered azacyclic derivative of the invention is an ideal JAK kinase inhibitor with a high potency, and can be used to treat or prevent diseases such as rheumatoid arthritis, polycythemia vera, psoriasis, primary thrombocytosis, myelofibrosis, and the like. The pyrrolopyrimidine five-membered azacyclic derivative has the general formula of formula I