The　performance-degradation　pattern　of　the　planetary　roller　screw　mechanism　(PRSM)　is　difficult　to　predict　and　evaluate　due　to　a　variety　of　factors.　Load-carrying　capacity,　transmission　accuracy,　and　efficiency　are　the　main　indicators　for　evaluating　the　performance　of　the　PRSM.　In　this　paper,　a　testing　device　for　the　comprehensive　performance　of　the　PRSM　is　designed　by　taking　into　account　the　coupling　relationships　among　temperature　rise,　vibration,　speed,　and　load.　First,　the　functional　design　and　error　calibration　of　the　testing　device　were　conducted.　Secondly,　the　PRSM　designed　in　the　supported　project　was　taken　as　the　research　object　to　conduct　degradation　tests　on　its　load-bearing　capacity　and　transmission　accuracy　and　analyze　the　changes　in　transmission　efficiency.　Third,　the　thread　profile　and　wear　condition　were　scanned　and　inspected　using　a　universal　tool　microscope　and　an　optical　microscope.　Finally,　based　on　the　monitoring　module　of　the　testing　device,　the　vibration　status　during　the　PRSM　testing　process　was　collected　in　real　time,　laying　a　foundation　for　the　subsequent　assessment　of　the　changes　in　the　performance　state　of　the　PRSM.　The　test　results　reveal　the　law　of　performance　degradation　of　the　PRSM　under　the　coupled　effects　of　temperature,　vibration,　speed,　and　load.