We　experimentally　demonstrate　a　high-power,　high-efficiency,　near-diffraction-limited　beam　quality　all-fiber　picosecond　pulse　laser,　which　consists　of　a　passively　mode-locked　seed　laser　and　three-stage　master　power　amplifiers.　A　repetition　frequency　multiplier　and　a　high　Yb-doped　gain　fiber　with　shorter　length　are　utilized　in　the　laser　system　to　suppress　the　nonlinear　effects　and　reduce　the　pulse　broadening　caused　by　dispersion.　Moreover,　the　homemade　light　mode　controllers　based　on　a　coiling　and　tapering　fiber　technique　and　the　active　fiber　of　the　amplifier　with　a　relatively　small　mode　area　are　adopted　to　improve　the　beam　quality.　In　addition,　by　experimentally　adjusting　the　active　fiber　length,　the　optical　conversion　efficiency　of　the　overall　laser　system　can　be　optimized.　Eventually,　a　160　W　high-power,　high-efficiency,　near-diffraction-limited　picosecond　pulse　fiber　laser　is　obtained,　with　the　beam　quality　factor　M-2　at　1.12　and　an　optical　conversion　efficiency　of　the　system　of　75%.　(C)　2016　Society　of　Photo-Optical　Instrumentation　Engineers　(SPIE)