Recently,　many　Video-on-Demand　(VoD)　service　providers　try　to　attract　as　many　users　as　possible　by　offering　multi-bitrate　video　streaming　services　with　differentiated　qualities.　Many　researches　focus　on　video　layered　coding　(e.g.,　scalable　video　coding,　SVC).　However,　SVC　is　not　widely　used　in　VoD　industry.　Another　solution,　multi-version　videos,　can　be　classified　into　online　transcoding　and　pre-stored　multi-version　videos.　Online　transcoding　is　a　CPU-intensive　and　costly　task,　so　it　is　not　suitable　for　large-scale　VoD　applications.　In　this　paper,　we　study　how　to　improve　caching　efficiency　based　on　pre-stored　multi-version　videos.　We　leverage　the　sharing　probability　among　different　versions　of　the　same　video　and　propose　a　multi-version　shared　caching　(MSC)　method　to　maximize　the　benefit　of　caching　proxy.　If　the　desired　version　is　not　in　the　cache　while　the　higher　neighbor　version　is　in,　MSC　transmits　the　higher　version　streaming　to　user　temporarily.　In　this　case,　MSC　can　make　full　use　of　the　caching　resources　to　improve　the　cache　hit　ratio　and　decrease　users＇　average　waiting　time.　Simulation　results　show　that　MSC　outperforms　the　others　in　the　cache　hit　ratio　and　the　average　waiting　time.