The results showed that GMSC‐Exo have the same or better effects in comparison with GMSC in reducing the incidence of arthritis and bone erosion in CIA mice by regulating the imbalance of Th17/Treg and inhibiting IL‐17RA‐Act1‐TRAF6‐NF‐κB signalling pathway. Here, TRAF3IP2 is linked to arthritic joint disease.