High　pulse-energy　semiconductor　saturable　absorber　mirror　passively　mode-locked　thulium-doped　femtosecond　fiber　laser　is　reported.　Based　on　a　linear　Fabry-Perot　cavity　by　the　combination　of　semiconductor　saturable　absorber　mirror　and　broadband　reflective　mirror,　the　thulium-doped　fiber　is　pumped　by　a　home-made　Er-doped　fiber　laser　at　1550　nm.　Stable　mode-locked　laser　pulse　train　occurs　at　312　mW　incident　pump　power　and　the　pulse　repetition　rate　is　53　MHz　in　such　a　linear　cavity　configuration.　When　the　incident　pump　power　is　472　mW,　the　maximum　output　power　is　50　mW,　corresponding　to　the　maximum　single　pulse　energy　of　0.94　nJ.　The　pulse　width　is　measured　to　be　907　fs;　the　laser　center　wavelength　and　the　3　dB　spectral　bandwidth　are　1939.5　nm　and　4.6　nm,　respectively.