TLR7/8/9 antagonist 2 is an orally active TLR7/8/9 antagonist. TLR7/8/9 antagonist 2 has inhibitory activities for HEK/hTLR7, HEK/hTLR8 and HEK/hTLR9 with IC 50 values of 0.011 μM, 0.029 μM and 0,052 μM, respectively.TLR7/8/9 antagonist 2 has high bioavailability in vivo.TLR7/8/9 antagonist 2 can be used for the research of auto-inflammatory diseases such as systemic lupus erythematosus or lupus nephritis.