We　reported　the　demonstration　of　high　average　power　picosecond　thulium-doped　fiber　amplifier　(TDFA)　at　2　μm　using　chirped　pulse　amplification　technique.　Here,　the　seed　laser　of　the　TDFA　is　an　all-fiber　passively　mode-locked　thulium-doped　fiber　laser　with　a　the　pulse　duration　of　63ps,　and　a　fundamental　repetition　rate　of　44MHz.　A　long　dispersion　compensating　fiber　with　large　positive　group　velocity　dispersion　β2　of　90　ps2/km　at　2000　nm　is　selected　to　broaden　the　pulse　duration.　Then,　after　two-stage　all-fiber　amplifiers,　we　obtain　an　unsaturated　maximum　output　power　of　73.5　W　with　an　optical-to-optical　slope　efficiency　of　49.8%　with　respect　to　absorbed　793　nm　pump　power.　The　pulse　duration　is　200　ps,　and　the　corresponding　peak　power　is　8.35　kW.　These　results　provide　an　excellent　pumping　source　for　the　applications　like　mid-infrared　supercontinuum　generation,　material　processing,　spectral　imaging,　and　so　on.　©　2019　IEEE.