High quality SrBi_(2)Ta_(0.6)Nb_(1.4)O_(9)(SBTN) ferroelectric thin films were fabricated on platinized silicon by PLD.Electrical fatigue and optical fatigue of SBTN ferroelectric thin films were studied,respectively.The fatigue mechanisms in the thin films were analyzed.The results indicate the excellent fatigue resistance of electrical properties under electrical fatigue for SBTN ferroelectric thin films.However,by using the illumination of a 200W Hg arc lamp at 0.9V,it was found that the average remanent polarization was dropped by nearly 51% due to the bias/illumination treatment.The optically induced polarization fatigue in SBTN films is due to trapping of photo-generated charge carriers at domain boundaries.