BACKGROUND : Studies have identified that the fibroblast-like synoviocytes (FLS) exhibited tumor-like characteristics and was the key factor in the pathogenesis of Rheumatoid arthritis (RA). GANT61, an antagonist of the sonic hedgehog pathway, has been verified with inhibitory effect on many cancers. Here we investigated the effect of GANT61 on FLS and the development of collagen-induced arthritis (CIA). METHODS : 40 Sprague Dawley (SD) rats were randomly divided into four groups: normal, CIA, CIA+10 mg/kg GANT61 and CIA+20 mg/kg GANT61. CIA was induced in rat with collagen injecting. The GANT61 was administered by intraperitoneal injection every 2 days for 3 weeks. The CIA model was identified with the paw swelling, arthritis score and the pathologic changes in joint. The FLS of different group were primary cultured. The proliferative capacity of FLS was detecteded via Cell Counting Kit-8 (CCK-8) method, and the apoptosis was detecteded by flow cytometry. The Bcl-2, Bax, Caspases3 and cleaved Caspases3 in synovium and FLS were detecteded by Western Blot. RESULTS : The 20 mg/kg GANT61 treatment reduced the incidence of CIA and relieved the arthritis symptoms in CIA rats. The Bcl-2 was upregulated and the Bax was downregulated in the CIA rats synovium. The 10 mg/kg and 20 mg/kg GANT61 diminished the Bcl-2 expression, 20 mg/kg GANT61 increased the Bax and activated the Caspases3 in the CIA synovium. The proliferation of CIA-FLS was significantly higher and the apoptosis of the CIA-FLS was lower than that of the control group. The 10 mg/kg and 20 mg/kg GANT61 treatment can reduce cell proliferation and induce apoptosis by diminishing Bcl-2 and increasing the Bax in CIA-FLS. CONCLUSIONS : The GANT61 inhibit the proliferation of FLS and alleviated the arthritic symptoms in CIA rats, this implied the GANT61 may be recommended as a possible candidate for the therapy of RA.