In　this　study,　a　type　of　multifunctional　mixed　micelles　were　prepared　by　a　novel　biodegradable　amphiphilic　polymer　(MPEG-SS-2SA)　and　a　multidrug　resistance　(MDR)　reversal　agent　(D-alpha-tocopheryl　polyethylene　glycol　succinate,　TPGS).　The　mixed　micelles　could　achieve　rapid　intracellular　drug　release　and　reversal　of　MDR.　First,　the　amphiphilic　polymer,　MPEG-SS-2SA,　was　synthesized　through　disulfide　bonds　between　poly　(ethylene　glycol)　monomethyl　ether　(MPEG)　and　stearic　acid　(SA).　The　structure　of　the　obtained　polymer　was　similar　to　poly　(ethylene　glycol)-phosphatidylethanolamine　(PEG-PE).　Then　the　mixed　micelles,　MPEG-SS-2SA/TPGS,　were　prepared　by　MPEG-SS-2SA　and　TPGS　through　the　thin　film　hydration　method　and　loaded　paclitaxel　(PTX)　as　the　model　drug.　The　in　vitro　release　study　revealed　that　the　mixed　micelles　could　rapidly　release　PTX　within　24　h　under　a　reductive　environment　because　of　the　breaking　of　disulfide　bonds.　In　cell　experiments,　the　mixed　micelles　significantly　inhibited　the　activity　of　mitochondrial　respiratory　complex　II,　also　reduced　the　mitochondrial　membrane　potential,　and　the　content　of　adenosine　triphosphate,　thus　effectively　inhibiting　the　efflux　of　PTX　from　cells.　Moreover,　in　the　confocal　laser　scanning　microscopy,　cellular　uptake　and　3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium　bromide　assays,　the　MPEG-SS-2SA/TPGS　micelles　achieved　faster　release　and　more　uptake　of　PTX　in　Michigan　Cancer　Foundation-7/PTX　cells　and　showed　better　antitumor　effects　as　compared　with　the　insensitive　control.　In　conclusion,　the　biodegradable　mixed　micelles,　MPEG-SS-2SA/TPGS,　could　be　potential　vehicles　for　delivering　hydrophobic　chemotherapeutic　drugs　in　MDR　cancer　therapy.