A　miniature　self-mixing　interferometer　based　on　microsphere　superlens　(MSSL)　for　the　displacement　measurement　of　microactuators　is　proposed.　The　interferometer　is　composed　of　a　taper　multimode　fiber　(TMMF)　and　MSSL　with　diameter　D　=　5　mu　m.　When　the　MSSL　is　irradiated　by　plane　wave　from　the　TMMF,　the　phenomenon　of　photonic　nanojet　(PNJ)　occurs.　The　PNJ　can　focus　on　the　surface　of　the　microactuator.　It　can　also　enhance　the　scattered　light　from　the　surface　of　the　microactuator,　and　enable　the　scattered　light　to　return　to　the　laser　cavity　to　generate　self-mixing　interference　phenomenon,　which　can　be　used　to　retrieve　the　displacement　detection　of　the　microactuator.　Experimental　results　show　that　the　relative　errors　are　more　accurate　than　1%　by　using　the　proposed　method