With　the　HTTP　adaptive　video　streaming　(HAS)　transmission　over　mobile　networks　being　widely　concerned　and　the　new　promising　technique　of　mobile　edge　computing　(MEC)　emerging,　the　problem　of　HAS　transmission　in　MEC-based　5G　networks　has　been　widely　studied.　However,　most　of　them　focus　on　the　issues　of　network　resource　utilization　and　the　quality　of　experience　(QoE)　promotion,　while　the　problem　of　energy　efficiency　is　largely　ignored.　In　this　paper,　different　from　previous　works,　by　taking　the　caching　and　transcoding　into　consideration,　we　propose　a　joint　caching　and　transcoding　schedule　strategy　for　HAS　delivery　in　MEC-enhanced　5G　network　to　realize　the　energy　efficiency.　We　formulate　the　problem　of　energy　efficient　joint　caching　and　transcoding　as　an　integer　linear　programming　problem　to　minimize　the　system　energy　consumption.　Then　to　make　the　NP-hard　problem　tractable,　we　introduce　a　heuristic　scheme　based　on　simulated　annealing　algorithm　to　iteratively　provide　the　global　optimum　solution.　Finally,　simulation　results　are　illustrated　to　show　that　our　proposed　strategy　presents　an　excellent　performance　and　provides　practical　significance　to　choose　proper　ways　of　responding　users＇　content　requests　according　to　different　hit　modes.　©　2018　IEEE.