AIM:To investigate the influence of transforming growth factor-β1(TGF-β1) on human orbital fibroblast(OF) by 3H-Pro absorption in vitro. ·METHODS:Human OF were cultured in vitro. Different concentrations of TGF-β1(0.1,1.0,5.0,10.0,100.0μg/L) were incubated with cultured human OF. The collagen synthesis was evaluated by 3H-Pro absorption. ·RESULTS:TGF-β1 of 0.1,1.0,5.0,10.0μg/L could promote the 3H-Pro absorption more than the control group while the concentration of TGF-β1 of 100.0μg/L had a different result.·CONCLUSION:There is a concentration-dependant effect between TGF-β1 and collagen synthesis of OF.