Novel compound of JAK kinase inhibitor

The invention relates to a novel compound of a JAK kinase inhibitor. The novel compound of the JAK kinase inhibitor is a compound shown in formula (I), pharmaceutically acceptable salt, prodrug, metabolite, isotope derivative and solvate of the compound and a pharmaceutical composition of the compound. The novel compound of the JAK kinase inhibitor can be used for preventing or treating diseases and conditions, relating to Janus kinase (JAK), in human patients and mammalian patients and can be applied to experiments in medicine, pharmacy, biology, physiology, biochemistry and so on as the Janus kinase (JAK) inhibitor.