Passively　mode-locked　fiber　laser　based　on　two-dimensional　material　MnPSxSey　saturable　absorber　is　studied.　By　changing　the　doping　ratio　of　S　and　Se,　three　magnetic　materials,　MnPS2.9Se0.1,　MnPS2.8Se0.2　and　MnPS2.7Se0.3,　are　obtained.　The　three　materials　were　fabricated　into　sandwich　absorbers,　and　stable　mode-locked　pulse　was　obtained　in　ytterbium-doped　fiber　lasers.　The　total　length　of　the　fiber　laser　is　88　m,　and　the　corresponding　repetition　rate　is　2.27　MHz　The　signal-to-noise　ratio　of　the　three　materials　is　all　above　60　dB,　indicating　the　stability　of　the　mode-locking　pulse.　The　experimental　results　show　that　MnPSxSey　has　good　nonlinear　optical　modulation　characteristics　and　optical　switching　ability,　which　has　potential　application　value.　©　2023　SPIE.