The present invention relates to a phenyl amino pyrimidine compound or a polymorph of a salt thereof, specifically, to N-(cyanomethyl)-4-(2-((4-(2', 2', 6', 6'-d4-morpholino)phenyl)amino)pyrimidin-4-yl)benzamide, or a pharmaceutically acceptable salt thereof, or a polymorph of a solvate thereof, that is, a compound shown in formula I or salt thereof, or a polymorph of a solvate thereof. The polymorph is suitable for preparing a pharmaceutical composition for suppressing non-receptor tyrosine kinases (such as JAK kinase).
