The present invention provides a series of JAK inhibitors, particularly compounds as shown in Formula (I) or its pharmaceutically acceptable salts, and applications thereof used in preparations of JAK realted diseases treatments.本發明公開了一系列JAK抑制劑,具體公開了式(I)化合物或其藥學上可接受的鹽及其在製備治療與JAK相關疾病的藥物中的應用。