Low-dimensional　(LD)　materials　show　the　extraordinary　properties　and　have　led　to　applications　in　the　fields　of　photonics,　optoelectronics　and　energy.　As　a　kind　of　zero-dimensional　(0D)　transition　metal　oxides,　MnFe2O4　nanoparticles　possess　various　magneto-optical　properties.　However,　the　nonlinear　optical　characteristics　as　well　as　the　applications　in　pulsed　lasers　have　never　been　studied　so　far.　Herein,　the　MnFe2O4　nanoparticles　with　diameter　of　10　nm　were　synthesized　by　the　thermal　decomposition　method.　The　MnFe2O4-microfiber　device　was　prepared　by　depositing　MnFe2O4　nanoparticles　on　a　microfiber,　whose　saturation　intensity/modulation　depth　was　measured　to　be　16.68　MW/cm2/19.64%.　Furthermore,　this　MnFe2O4-microfiber　device　was　used　to　generate　passively　Q-switching　laser　pulses　in　Er-doped　fiber　(EDF)　laser.　Under　the　pump　power　of　80–780　mW,　the　pulse　duration/repetition　rate　varies　from　4.76　μs/73.1　kHz　to　622　ns/230.9　kHz.　The　largest　output　power　is　29.75　mW.　The　70　dB　signal-to-noise　ratio　(SNR)　verifies　the　stability　of　Q-switching　operation.　This　work　is　the　first　demonstration　of　using　MnFe2O4　nanoparticles　as　saturable　absorber　(SA)　in　designing　Q-switching　laser.　Compared　to　recent　reported　Q-switching　EDF　lasers　with　LD　materials,　our　work　shows　some　improvements.　These　experimental　results　demonstrate　that　MnFe2O4　nanoparticles　can　be　developed　as　an　efficient　SA　materials　and　have　potential　photonics　applications.　©　2020　Elsevier　B.V.