Laser induced damage thresholds (LIDTs) and photo-induced changes of AS(40)S(60), Ga0.8As39.2S60 and Ga0.8As29.2Sb10S60 chalcogenide glasses are investigated by femtosecond laser of 800nm. AS(40)S(60) glass has the highest LIDT as well as 1452.3 mJ/cm(2), the introduction of small amount of Ga and Sb into glass decreases the LIDTs to 957.1 mJ/cm(2) for Ga0.8As39.2S60 and 705.9 mJ/cm(2) for Ga0.8As29.2Sb10S60, respectively. Microstructure analysis reveals that the decrease of LIDT is tightly related to the decrease of high strength chemical bonds and formation of lower ones in glass matrix. After multi pulses induced damage occurred, the structure of glass matrix became more random and a half of S was replaced by O approximately. The damage mechanism was proposed and it is helpful to develop high LIDT chalcogenide glasses and the photo-induced effects are the basis of waveguide writing in chalcogenide glasses by femtosecond laser. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement