Provided is a thiobenzopyran-based compound of Formula I and its pharmaceutically acceptable salt, and its use in the preparation of drugs for the treatment of rheumatoid arthritis, wherein X is selected from oxygen, sulfur, —SO—, and —SO2—; Y is a sulfur atom and Z is H, Na, or K. Through preliminary tests of anti-inflammatory activity, compounds of formula I have anti-rheumatoid arthritis effects.