In conclusion, our study revealed the similar transition processes of SFs in both RA and OA, described the corresponding changes of the functional states in the transition process, and indicated the potential regulatory effects of the WNT signaling pathway, the TGF-β signaling pathway, the FcεRI signaling pathway, and the ERBB signaling pathway on the transition of synovial fibroblasts in both RA and OA, which may provide potential therapeutic targets to both conditions. Here, EGFR is linked to rheumatoid arthritis.