Nowadays,　sustainability　has　become　an　important　and　widely　accepted　concept.　Energy　conservation　and　emission　reduction　are　closely　related　to　sustainable　economic　development.　Therefore,　a　3E　efficiency　approach,　based　on　the　＂Energy-Environmental-Economic＂　(3E)　system,　can　assess　the　coordination　relationships　among　these　three　factors　from　the　perspective　of　energy　conservation　and　emission　reduction.　The　digital　economy　is　a　new　driving　force　for　economic　growth,　but　few　studies　have　dealt　with　the　question　on　whether　it　affects　3E　efficiency.　The　purpose　of　this　paper　is　to　examine　the　relationship　between　the　digital　economy　and　3E　efficiency　in　EU　countries.　The　empirical　results　indicate　that:　(1)　overall　3E　efficiency　of　EU　countries　showed　an　upward　trend　from　2011　to　2019;　(2)　in　terms　of　the　relationship　between　the　digital　economy　and　3E　efficiency,　the　digital　economy　has　direct　and　indirect　(through　economic　growth)　impacts　on　3E　efficiency;　when　GDP　per　capita　exceeds　EUR　15,580,　the　influence　coefficient　of　the　digital　economy　on　3E　efficiency　changes　from　negative　to　positive.　This　suggests　that　EU　countries　with　different　levels　of　economic　development　should　adopt　different　strategies　to　ensure　the　simultaneous　development　of　their　digital　economy　and　3E　efficiency.